摘要:

14 Biological Chemistry Part (ii) Insect Chemistry By R. BAKER and D. A. EVANS Department of Chemistry University of Southampton Southampton S.095NH 1 Introduction Since the last Annual Report on this topic,’ it has become increasingly apparent that the role of chemicals in the mediation of insect behaviour is immeasurably more complex than imagined earlier and that current knowledge allows us to construct only a superficial understanding of insect life. This Report selectively reviews some major advances reported in the past two years and the scope of coverage remains broadly similar to the 1975 Report. Several books articles and reviews have appeared in the meantime particularly in the areas concerned with pest management methods and plant-insect interactiom2 2 Sex Attraction and Related Phenomena The sex pheromones of moths and butterflies (Lepidoptera) have again proven to be a fruitful area of st~dy,~ and the Table lists structures from several detailed examinations.All are C12 CI4 c16 or C18straight-chain alcohols acetates or aldehydes with the exception of (la) and (Ib) from the Peach Fruit Moth Carposina niponensi~,~ and (2) and (3) .from the Potato Tuberworm Moth Phthorimaea operculella (species C in the Table) In addition to a pyrrolizidine alkaloid (4) reported earlier the hairpencil secretion of the butterfly Amauris ochlea contains inter alia methyl salicylate eugenol and cis-jasmone (5).6 In Danaus species pyrrolizidine alkaloids in food ’ R. Baker and D. A. Evans Ann. Reports (B) 1975,72,347.* ‘Animal Communication by Pheromones’ H. H. Shorey Academic Press London 1976; ‘Chemical Control of Insect Behaviour; Theory and Application’ H. H. Shorey and J. €3. McKelvey jun. Wiley New York 1977; ACS Symp. Ser. 1976 No. 23 ‘Pest Management with Insect Sex Attractants and Other Behaviour Controlling Chemicals’ (Symposium 1975); ACS Symp. Ser. 1977 No. 37 ‘Pesticide Chemistry in the 20th Century’ (Symposium 1976); Recent Adv. Phytochem. 1976,10 ‘Biochemical Interaction of Plants and Insects’; J. W. Wheeler Lloydia 1976 39 53; B. Tursch J. C. Braekman and D. Daloze Experientia 1976 32,401. ’W. L. Roelofs and R. T. Cardi Ann. Rev. Entomol. 1977 22 377; J. Weatherston and J. Percy Endeavour 1977.83. Y. Tamaki K. Honma and K. Kawasaki Appl.Entomol. Zool. 1977,12,60. C. J. Persoons S. Voerman P. E. J. Verwiel F. J. Ritter W. J. Nooijen and A. K. Minks Entomol. Exp. Appl. 1976 20 289; R. Yamaoka H. Fukami and S. Ishii Agric. and Biol. Chem. (Japan) 1976 40 1971; W. L. Roelofs J. P. Kochansky R. T. CardC G. G. Kennedy C. A. Henrick J. N. Labovitz and V. L. Corbin Life Sci. 1975 17 699. R. L. Petty M. Boppre D. Schneider and J. Meinwald Experientia 1977 33 1324. 367 R. Baker and D. A. Evans Table Some sex pheromone attractants of Lepidoptera species Parent Terminal chain functional length group Unsaturation Cl2 c13 c14 Acetate Acetate Alcohol (21-9(E,E)- 8,lO (E,Zb4,7(E,Z,Z)-4,7,10 - (€)-11 Acetate (Z)- 1 1 (2,E)-9,12 - (E)-9 (21-9(E)-1 1 c16 Aldehyde Alcohol Acetate (Z)- 1 1 (E,E)-9,11 (Z,E)-9,12 (21-7(E)- 1 1 (2)-11 (2)-11 (Z1-9(E)- 1 1 (2)-1 1 cl8 Aldehyde Aldehyde (2)-1 1 (E,Z)-6,11 (E,Z)-6,11 (2)-13 Species A Eupoecilia ambiguella ; B Rhyacionia rigidana ;C Phthorimaea operculella ; D Platynota PaVedanu; E Archips rosana; F Ephestia cautella; G Ostrinia nubilalis (Iowa); H Pandemis limitata; I Pandemis pyrusana ;J Naranga aenescens; K Epiphyas postvittana ;L,Archippus breviplicanus; M Prays citri; N Choristoneura fumiferana ;0,Scotogramma trifolii; P,Brachmia macroscopa ;Q Sesamia inferens ; R Antheraea polyphemus; S Chilo suppressalis; T,Heliothis armigera.a H. Am S. Rauscher H. R. Buser and W. L. Roelofs 2.Naturforsch. 1976,31c 9; A. S. Hill C. W. Berisford U. E. Brady and W. L. Roelofs Environ. Entomol.1976,5,959; C. J. Persoons S. Voerman P. E. J. Verwiel F. J. Ritter W. J. Nooijen and A. K. Minks Entomol. Exp. Appl. 1976,20 289; see also R. Yamaoka H. Fukami and S. Ishii Agric. and Biol. Chem. (Japan) 1976,40 1971 and W. L. Roelofs J. P. Kochansky R. T. Cardi G. G. Kennedy C. A. Henrick J. N. Labovitz and V. L. Corbin Life Sci. 1975,17,699; A. S. Hill R. T. CardC W. M. Bode and W. L. Roelofs J. Chem. Ecol. 1977,3,369;'W. L. Roelofs A. S. Hill A. Cardi R. T. Cardt J. Vakenti and H. Madsen Environ. Entomol. 1976,5,362; J. S. Read and C. P.Haines J. Stored Product Res. 1976. 12 49; see also ibid. p. 55; J. A. Klun and G. A. Junk J. Chem. Ecol. 1977 3 447; W. L. Roelofs A. Cardt A. S. Hill and R. T. Cardt Environ. Entomol. 1976 5 649; W.L. Roelofs R. F. Lagier and S. C. Hoyt ibid. 1977 6 353; T. Ando K. Kishino S. Tatsuki H. Nakajima S. Yoshida and N. Takahashi Agric. and Biol. Chem. (Japan) 1977,41 1819; 'R. J. Bartell and L. A. Lawrence Physiol. Entomol. 1977 2 89; H. Sugie K. Yaginuma and Y. Tamaki Appl. Entomol. Zool. 1977 12 69; B. F. Nesbitt P. S. Beevor D. R. Hall R. Lester M. Sternlicht and S. Goldenberg Insect Biochem. 1977,7 355; C. J. Sanders and J. Weatherston Canad. Entomol. 1976,108 1285; see also Compt. rend. 1975,281 D 1111; E. W. Underhill W. F. Steck and M. D. Chisholm Environ. Entomol. 1976 5,307; 'C. Hirano H. Muramoto and M. Horiike Naturwiss. 1976,63,439; B. F. Nesbitt P.S. Beevor D. R. Hall R. Lester and V. A. Dyck Insect Biochem. 1976 6 105; J. Kochansky J. Tette E.F. Taschenberg K. E. Kaissling and W. L. Roelofs J. Insect Physiol. 1975 21 1977; 'B. F. Nesbitt P. S. Beevor D. R. Hall R. Lester and V. A. Dyck J. Insect Physiol. 1975 21 1883; K. Ohta S. Tatsuki K. Uchiumi M. Kurihara and J. Fukami Agric. and Biol. Chem. (Japan) 1976 40 1897; P. Piccardi A. Capizza G. Cassani P. Spinelli E. Arsura and P.Massardo J. Insect Physiol. 1977 23 1443. Biological Chemistry-Part (ii) Insect Chemistry 369 plants are postulated to contribute to the unpalatability of these butterflies to potential predators.' Specialized organs on the hindwings of male Ithomiinae butterflies secrete the lactone (6)which is structually related to the esterifying acids of pyrollizidine alkaloids.8 0 R (1) a; R = n-CgHl9 b; R = n-C8HI7 0 I The differences of sex attractant responses of Grapholitha molesta male moths to subtle changes in component ratio of a binary pheromone have been attributed to a normal distribution of responses about an optimum mixture rather than to genetic variation within a single species.' Furthermore two Archips sibling species main- tain reproductive isolation by employing different blends of the same chemicals as sex pheromones.lo The effects of enantiomeric'l and geometric12 composition on response have also been investigated. Attractants have been discovered for many economically important moth species as a result of screening programrne~.'~ The Eastern Tent Caterpillar Malacosoma americanum forages by preception of chemicals present in trails of silk leading from the communal tent to distant food sources.l4 Many male Noctuid moths possess eversible glandular structures and the genital scent brushes of several species release oxygenated aromatic compounds (e.g. 2-phenylethanol) which elicit sexual behaviour in the females of those spe- cie~.~~ ' J. A. Edgar P. A. Cockrum and J. L. Frahn Experientia 1976,32 1535. * J. A. Edgar C. C. J. Culvenor andT. E. Pliske J. Chem. Ecol. 1976,2 263. ' R. T. Card& T. C. Baker and W. L. Roelofs Experientia 1976,32 1406. lo R. T. Card& A. M. CardC A. S. Hill and W. L. Roelofs J. Chem. Ecol. 1977,3 71. 11 D. Klimetzek G. Loskant J. P. Vite and K. Mori Naturwiss. 1976 63 581. 12 R. T. Card& and W. L. Roelofs J. Chem. Ecol. 1977,3 143. 13 E.W. Underhill M. D. Chisholm and W. Steck Enuiron. Entomol. 1977 6 333; K. Yaginuma M. Kurnakura Y. Tamaki T. Yushima and J. H. Tumlinson Appl. Entomol. Zool. 1976 11,266; L. I. Butler J. E. Halfhill L. M. McDonough and B. A. Butt J. Chem. Ecol. 1977,3,65;W. Steck E. W. Underhill B. K. Bailey and M. D. Chisholm Enuiron. Entomol. 1977 6 270; V. E. Adler M. Jacobson J. F. Edrniston and M. H. Fleming J. Econ. Entomol. 1976 69 706; A. K. Minks S. Voerman and M. Van de Vrie Entomol. Exp. Appl. 1976 19 301; W. F. Steck B. K. Bailey E. W. Underhill and M. D. Chisholm Enuiron. Entomol. 1976,5,523; W. L. Roelofs W. H. Reissig and R. W. Weires ibid. 1977 6 373; R. E. Doolittle W. L. Roelofs J. D. Solomon R. T. CardC and M. Beroza J. Chem. Ecol. 1976,2 399. 14 T.D. Fitzgerald and E. M. Gallagher J. Chem. Ecol. 1976 2 187. 15 M. Jacobson V. E. Adler A. N. Kishaba and E. Priesner Experientia 1976,32,964;H. J. Bestrnann 0.Vostrowsky and H. Platz ibid. 1977 33 874. R. Baker and D. A. Evans In the Coleoptera alcohols and hydrocarbons are employed by female boll weevils (Anthonomus grandi:) as sex attractants for males.16 Further investigations of several species of Trogoderma Dermestid beetles have shown the importance of (7a) and (7b) in addition to1s:ompounds reported earlier in mating behavi~ur,~'*'' and an informative summary of the chemical basis for interspecific and intraspecific responses has been presented." A major sex-attracting component produced by virgin female Attagenus elungatus beetles is reported as (8),20whereas the female Japanese Beetle Pupillia japonica employs (9) as a sex pheromone.21 It is reported in this context that racemic (9)is completely inactive whereas the (S)-enantiomer is inhibitory.Aromatic derivatives including (1 0) are male-specific natural products in the bug Leptoglossus phyllopus.22 CHO (7a) (7b has E-geometry) 0LJ...J8"" H Me0 QOMe OH (9) (10) Pest species of flies have again attracted considerable attention. Females of the stable fly species Stomoxys calcitrans produce a mating stimulant consisting of methyl-branched and 1,5-dimethyl-branched hydrocarbons of which 1S-methyl-tritriacontane and 15,19-dimethyltritriacontaneare most active in behavioural bioa~says.~~ In this context it is interesting to note that (2,Z)-pentacosa- 1,7,13- triene is a major cuticular wax component for males of this species but is absent in The mating-stimulant pheromones and cuticular lipid constituents of the Little House Fly Fannia canicularis have been investigated.Newly emerged l6 G. H. McKibben P. A. Hedin W. L. McGovern N. M. Wilson and E. B. Mitchell J. Chem. Ecol. 1977 3 331. l7 J. H. Cross R. C. Byler R. F. Cassidy jun. R. M. Silverstein R. E. Greenblatt W. E. Burkholder A. R. Levinson and H. 2.Levinson J. Chem. Ecol. 1976 2,457. R. E. Greenblatt W. E. Burkholder J. H. Cross R. C. Byler and R. M. Silverstein J. Chem. Ecol. 1976; 2 285; J. H. Cross R. C. Byler R. E. Greenblatt J. E. Gorman and W. E. Burkholder ibid. 1977 3 115. f9 R. E. Greenblatt W.E. Burkholder J. H. Cross R. F. Cassidy jun. R. M. Silverstein A. R. Levinson and H. Z. Levinson J. Chem. Ecol. 1977,3 337. 2o H. Fukui F. Matsumura A. V. Barak and W. E. Burkholder J. Chem. Ecol. 1977 3 539. *' J. H. Tumlinson M. G. Klein R. E. Doolittle T. L. Ladd and A. T. Proveaux Science 1977 197 789. 22 J. R. Aldrich M. S. Blum S. S. Duffey and H. M. Fales J. Insect Physiol. 1976 22 1201. 23 P. E. Sonnet E. C. Uebel R. L. Harris and R. W. Miller J. Chem. Ecol. 1977 3 245. 24 P. E. Sonnet E. C. Uebel and R. W. Miller J. Chem. Ecol. 1977,3,251. Biological Chemistry-Part (ii) Insect Chemistry 371 adults of both sexes have identical lipid constituents but considerable differences are apparent after five days. (2)-9-Pentacosene constitutes 66% of female lipids compared to 1% in males and this component is suggested as a sex pheromone.” The long-running saga of the sex pheromone of the American Cockroach Periplaneta americana has been advanced by the proposal of (11) as a tentative structure.26 Interestingly the structurally related germacrene-D (12) has been found to be a phytochemical sex-stimulant for this specie^.'^ (1 1) (12) The chemistry of the metasternal gland of the Eucalypt Longhorn Phorocantha synonoma has been studied and the existence of several lactones [e.g.(13)] has (13) I/ been demonstrated.28 A second component of the sex pheromone of the German Cockroach Blattella germanica has been shown to be (14).29 3,7-Dimethyl-HO(CH2)17CH(CH&CHCOMe I I Me Me (14) pentadecan-2-01 (15) plays a key role in the sexual behaviour of three sawfly species and inter-species specificity is based upon pheromone blends of (15) and the corresponding acetate and propionate esters.30 (15) ’ 25 E.C. Uebel P. E. Sonnet R. E. Menzer R. W. Miller and W. R. Lusby J. Chem. Ecol. 1977,3,269. 26 C. J. Persoons P. E. J. Verwiel F. J. Ritter E. Talrnan P. J. F. Nooijen and W. J. Nooijen Tetrahedron Letters 1976 2055. ’’C.Kitamura S. Takahashi S. Tahara and J. Mizutani Agric. and Biol. Chem. (Japan) 1976 40 1965; C. Nishino T. R. Tobin and W. S. Bowers J. Insect Physiol. 1977,23,415. B. P. Moore and W. V. Brown Austral. J. Chem. 1976,29 1365. 29 R. Nishida T. Sato Y. Kuwahara H. Fukami and S. Ishii J. Chem. Ecol. 1976 2 449.30 D. M. Jewett F. Matsumura and H. C. Coppel Science 1976,192 51. R. Baker and D. A. Evans 3 Aggregation Pheromones and Population Attractants This complex area of interplay between host phytochemicals and pheromones has continued to attract considerable The aggregation pheromone complex reported earlier’ for the European Elm Beetle Scolytus multistriatus is also associated with the Larger European Elm Beetle S. sc~lytus.~~ The availability by synthesis (Section 13) of enantiomers and isomers of bark-beetle pheromones has enabled testing of response ~pecificity.~~ The dioxaspirononane (16) has been (16) reported as an aggregation pheromone of Pityogenes chalcographus a pest of Norway spruce.35 4 Pheromones of Social Insects and Related Species The complexity of chemosensory communication is amply illustrated by detailed investigations of the behaviour of social insects.36 Chemical and ethological studies of the Dufour’s gland secretion of the ant Myrmica rubra have related specific behavioural responses to individual components of the ~ecretion.~’ The male mandibular gland secretion of the ant Camponotus clavithorax is a complex mixture containing (17),38 whereas the volatiles associated with two Formica species are largely monoterpenoids together with methyl 3-isopropylpentanoate (1 8).39 Alarm pheromone components have been reported for several ant species,4o including (19) for eight Formica specie^,^' and (20) for Hypoponera opacior and Ponera pennsyl~anica.~~ The lactone (21) occurs together with terpenoids in the mandi- bular gland secretion of carpenter bees.43 A number of terpenoid alcohols and esters have been implicated in flight-marking in bumblebee^,^^ and neral and 31 J.P. Vite and W. Francke Nuturwiss. 1976 63 550. 32 C. M. Harring J. P. Vite and P. R. Hughes Nuturwiss. 1975 62 488; J. A. A. Renwick G. B. Pitman and J. P. Vite ibid. 1976,63 198; J. A. A. Renwick J. P. Vite and R. F. Billings ibid. 1977 64 226; M. C. Birch P. E. Tilden D. L. Wood L. E. Browne J. C. Young and R. M. Silverstein J. Insect Physiol. 1977 23 1349. 33 M. M. Blight F. A. Mellon L. J. Wadhams and M. J. Wenham Experientiu 1977,33 845. 34 D. L. Wood L. E. Browne B. Ewing K. Lindahl W. D. Bedard P. E. Tilden K. Mori G. B.Pitman and P. R. Hughes Science 1976,192 896; J. H. Borden L. Chong J. A. McLean K. N. Slessor and K. Mori ibid. p. 894; G. N. Lanier W. E. Gore G. T. Pearce J. W. Peacock and R. M. Silverstein J. Chem. Ecol. 1977.3 1. 35 W. Francke V. Heeman B. Gerken J. A. A. Renwick and J. P. Vite Nuturwiss. 1977,64,590. 36 Proceedings of the 8th International Conference of the International Union for the Study of Social Insects Wageningen Netherlands 1977; published by the Centre for Agricultural Publishing and Documentation Wageningen. 37 M. C. Cammaerts-Tricot E. D. Morgan R. C. Tyler and J. C. Braekman J. Insect Physiol. 1976 22 927; see also ibid. 1977 23 511. 38 H. A. Lloyd M. S. Blum and R. M. Duffield Insect Biochem. 1975 5,489. 39 M. Buehring W.Francke and V. Heeman 2.Nuturforsch. 1976,31c 11. 40 J. Lofquist J. Insect Physiol. 1976 22 1331; N. Hayashi and H. Komae Experientiu 1977 33,424. 41 R. M. Duffield J. M. Brand and M. S. Blum Ann. Entomol. SOC.Amer. 1977 70 309. 42 R. M. Duffield M. S. Blum and J. W. Wheeler Comp. Biochem. Physiol. (B) 1976 54,439. 43 J. W. Wheeler S. L. Evans M. S. Blum H. H. V. Velthuis and J. M. F. de Camargo Tetrahedron Letters 1976 4029; see also Ann. Entomol. SOC. Amer. 1977 70,635. 44 B. G. Svensson and G. Bergstrom Insectes Sociuux 1977,24 213. Biological Chemistry -Part (ii) Insect Chemistry geranial have been suggested as components of the sex pheromone of the parasitic wasp Itoplectis conq~isitor.~~ Faranal (22) reminiscent of a juvenoid is proposed as a trail pheromone of Pharaoh’s Ant Monomorium pharaoni~.~~ The configuration of the two adjacent methyl groups was established to be as shown (or its antipode) by comparison of the ozonolysis product of faranal with that of trans-3,4-dimethylcyclohexene.C0,Me 5 Alarm Behaviour in Aphids Alarm behaviour in aphid species has been extensively studied. When attacked by predators aphids of the Therioaphis genus secrete droplets containing (-)-germacrene-A (23).47 Sesquiterpenoid hydrocarbons such as (E)-P-farnesene (24) function as alarm pheromones in aphids and norfarnesenes also elicit this response.48 It is considered unlikely that such compounds are sufficiently stable for field use in control methods. 6 Defence Secretions Defence secretions are generally produced by insects in much larger quantities than sex pheromones.This consideration together with the impetus provided by the possibility of uncovering novel insecticides accounts for the relatively large number of intricate and diverse structures elucidated in this area. An interesting review on arthropod protective agents has appeared.49 4s D. C. Robacker and L. B. Hendry J. Chem. Ecol. 1977 3 563. 46 F. J. Ritter I. E. M. Bruggemann-Rotgans P. E. J. Verwiel C. J. Persoons and E. Talman Tetrahedron Letters 1977 2617. 47 W. S. Bowers C. Nishino M. E. Montgomery L. R. Nault and M. W. Nielson Science 1977 196 4290; see also J. Chem. Ecol. 1977.3 349. 48 C. Nishino W. S. Bowers M. E. Montgomery and L. R. Nault Agric.and Biol. Chem. (Japan) 1976 40 2303; see also J. Insect Physiol. 1977 23 697; Appl. Entomol. Zool. 1976 11,340. 49 H. Schildknecht Angew. Chem. Internat. Edn. 1976,15 214. R. Baker and D. A. Evans The defensive substances of the Opilionids Leiobunum uentricosum and Hadro -bunus maculosus are reported as (25a) and (25b) in addition to 4-methylheptan-3- one.” In ants components of defence secretions range from simple aliphatic compounds in Formica species 51 to iridoid monoterpenoid~~~ such as iridomyr- mecin (26) and dolichodial (27).53 The powerful alkaloidal venoms of fire ants have Rd.Jy 0-FCHO EO CHO (25) a; R=Me HO b; R=Et (26) (27) been inter-related chemotaxonomically,54 and a South African species (Solenopsis punctaticeps) has been shown to contain a novel series of 2,5-dialkyl-pyrrolidines and -pyrrolines (28a-d) and (29a b and c).” Ladybugs indigenous to Canada R’LA N R2 H (28) a; R’ = C2,R2= C5 (29) a; R’ = C4,R2 = C5 b; R’ = Cg R2 = C2 b; R’ = Cz R2= C7 c; R’ = Cz R2= C7 C;R’= c4,R~= C d; R’ = C7 R2= C2 Numbers refer to length of n-alkyl chain (Hippodamia caseyi) have been found to utilize a series of defensive alkaloids [e.g.(30) (3l)],closely related to structures discovered earlier.56 Quinone and hydro- carbon defence chemicals from five genera of bombardier beetles have been (30) (31) listed,57 and the cyclopentanoid monoterpenoids chrysomelidial (32) and plagiolactone (33) are components of the larval defensive secretion of the chry- T.H. Jones W. E. Conner A. F. Kluge T. Eisner and J. Meinwald Experientia 1976 32 1234. J. Lofquist Oikos 1977 28 137. ’’ J. W. Wheeler T. Olagbemiro A. Nash and M. S. Blum J. Chem. Ecol. 1977,3 241. 53 G. W. K. Cavill E. Houghton F. J. McDonald and P. J. Williams Insect Biochern. 1976,6 483. s4 J. G. MacConnell M. S. Blum W. F. Buren R. N. Williams and H. M. Fales Toxicon 1976,14 69. ” D. J. Pedder H. M. Fales T. Jaouni M. S. Blum J. G. MacConnell and R. M. Crewe Tetrahedron 1976,32,2275. 56 W. A. Ayer M. J. Bennett L. M. Browne and J. T. Purdham Canad. J. Chem. 1976,54 1807. ” T. Eisner T. H. Jones D. J. Aneshansley W. R. Tschinkel R. E. Silberglied and J. Meinwald J. Insect. Physiol. 1977 23. 1383. Biological Chemistry -Part (ii) Insect Chemistry somelid beetle Plagiodera ver~icolora.~~ The water beetle Platambus maculatus uses platambin (34) in a defensive a full report of the defensive behaviour of Stenus comma has also appeared.60 (E)-Oct-2-enal and (E)-hex-2-enal are present in the defensive scent of the Black Stink Roach a New Zealand cockroach sDecies.6 yLoCHO %o 0 * i>H (32) (33) (S s-?) (34) It has long been recognized that the defensive secretions of many termite species contain complex oxygenated diterpenoids.In particular the sprays ejected at attackers by the nozzle-like heads of nasute soldiers frequently contain such substances. Several of these structures have been elucidated by X-ray methods in conjunction with microchemical studies. The soldier caste of the termite Tri-nervitermes gratiosus contains in addition to five monoterpenoids,62 an intriguing series of novel diterpenoids [e.g.(35)] based on the ‘trinervitene’ ~keleton.~~ The soldiers of Nasutitermes kempae the structurally related isomers of (36).The frontal gland defence secretion of Macrotermes subhyalinus contains a mixture of alkanes and alkene~,~~ whereas Schedorhinotermes species produce long-chain enones [e.g. (37)] and ketones.66 (35) (36) (37) 7 Host Food Host Prey and Oviposition Attractants On the whole the investigations of chemical signs which are used by phytophagous insects in host selection have advanced surprisingly slowly over the past few years. J. Meinwald T. H. Jones T. Eisner and K. Hicks Proc. Nut. Acad. Sci.U.S.A. 1977 74 2189. 59 H. Schildknecht H. Holtkotte and D. Krauss Ann. Chem. 1975 1850. 6o H. Schildknecht D. Burger D. Krauss and J. Connert J. Gehlhaus and H. Essenbreis J. Chem. Ecol. 1976 2 1. M. H. Benn R. F.N. Hutchins and R. Folwell J. Insect Physiol. 1977,23 1281. 62 G. D. Prestwich Insect Biochem. 1977,7 91. 63 G. D. Prestwich S. P. Tanis J. P. Springer and J. Clardy J. Amer. Chem. Soc. 1976 98 6061; see also ibid. p. 6062. 64 G. D. Prestwich B. A. Solheim J. Clardy F. G. Pilkiewicz Z. Miura S. P. Tanis and K. Nakanishi 1.Amer. Chem. SOC.,1977,99,8082. 65 G. I).Prestwich B. A. Bierl E. D. Devilbiss and M F. B. Chaudhury J. Chem. Ecol. 1977 3,579. 66 G. D. Prestwich M. Kaib W. F. Wood and J. Meinwald Tefruhedron Letters 1975 4701. R.Baker and D. A. Evans It has been reported that the attraction of adult Cabbage Maggots Hylemya brassicae is mediated by ally1 isothiocyanate whereas oviposition is induced by plant glucosinolates.67 Dipropyl disulphide released by leek leaves stimulates significant egg-laying behaviour in the leek moth Acrolepiopsis assectella.68 A detailed study of Indian Calamus Root oil has unearthed a number of compounds which are attractants of fruit-fly species [e.g.acroagermacrone (38)].69 (38) Chemical cues used by parasitoids of insects have received considerable attention (e.g. ref. 70). The parasitoid Biosteres longicaudatus locates its fruit-fly host by perception of fermentation products of rotting Kairomones used by parasi- toids have been found in food plants of the host insects and it has been proposed on the basis of radiotracer evidence that such kairomones are ingested concen- trated and then released unaltered by the A case of aggressive chemical mimicry has been reported for a female Masto-phora spider which attracts prey with a volatile substance which apparently mimics the female-produced sex attractant of the Fall Armyworm Spodoptera frugiperda.This hypothesis is corroborated by the observation that only males of the latter species are trapped and that these are attracted from downwind both points being characteristic of mating beha~iour.~~ 8 Antifeedants and Repellants The interactions between plants and insects have been reviewed.74 There have been numerous reports of antifeedant and insecticidal activity of plant constituents but coverage here is limited to compounds which have pronounced effects suppor- ted by bioassay results.Quinones [e.g. (39)] are constituents of pest-resistant strains of cotton and are associated with insecticidal and larval growth-inhibitory 67 K. S. S. Nair and F. L. McEwen Canad. Entomol. 1976 108 1021. J. Boscher Compt. rend. 1977,284 D 635. " M.Jacobson I. Keiser D. Miyashita and E. J. Harris Lloydia 1976 39 412. 70 R. D. Henson S. B. Vinson and C. S. Barfield J. Chem. Ecol. 1977,3 151. 71 P.D. Greany J. H. Tumlinson D. L. Chambers and G. M. Bousch J. Chem. Ecol. 1977,3 189. 72 L. B. Hendry J. K. Wichmann D. M. Hindenlang K. M. Weaver and S. H. Korzeniowski J. Chem. Ecol. 1976 2 271. 73 W. G.Eberhard Science 1977,198 1173. 74 H. Z. Levinson Experientia 1976 32 408. Biological Chemistry -Part (ii) Insect Chemistry proper tie^.^^ Four dialdehydes [e.g.muzigadial (40)]have been reported as potent armyworm anti feed ant^.^^ Nic-1 (41) is one of a number of oxygenated steroids from the plant Nicandra physaloides which has an inhibitory effect on larval feeding,77 and harrisonin (42) is reported to have similar proper tie^.^^ Diter-CHO ] \ 0 'OH HI / HO "0 (41) Denoids have also been implicatec in host-p.mt resistance and antifeedant beha~iour.~~ Oviposition deterrents" and inhibitors" represent relatively new areas of study and it is felt that such responses might be important in developing novel control methods.9 Biosynthesis and Biotransformation A major point of controversy has centred on the possibility that pheromones of the Lepidoptera may be derived from the diet.82 Subsequent examination of this postulate established that the 67 :33 (E)-ll-:(2)-11-tetradecenyl acetate pheromone composition of the Oak Leaf Roller did not vary irrespective of whether the insect had been reared on oak leaves or an artificial diet thus sugges- ting specific biosynthe~is.~~ Indeed a re-examination of previous results now accords to the latter view.84 The biosynthesis of the hairpencil pheromone 7s R. D. Stipanovic A. A. Bell D. H. O'Brien and M. J. Lukefahr Tetrahedron Letfers 1977 567; J. R. Gray T. J. Mabry A. A. Bell R. D. Stipanovic and M. J. Lukefahr J.C.S. Chem.Comm.,1976 109. 76 I. Kubo 2.Miura M. J. Pettei Y.W. Lee F. Pilkiewicz and K. Nakanishi Tetrahedron Letters 1977 4553; I. Kubo Y. W. Lee M. J. Pettei F. Pilkiewicz and K. Nakanishi J.C.S. Chem. Comm. 1976 1013. 77 M.J. Begley L. Crombie P.J. Ham and D. A. Whiting J.C.S. Perkin I 1976 296 304. 78 I. Kubo S. P. Tanis Y. W. Lee I. Miura K. Nakanishi and A. Chapya Heterocycles 1976,5,485. 79 I. Kubo I. Miura K. Nakanishi T. Kamikawa T. Isobe and T. Kubota J.C.S. Chem. Comm. 1977 555; A. C. Waiss jun. B. G. Chan C. A. Elliger V. H. Garrett E. C. Carlson and B. Beard Nuturwiss. 1977,64 341; T. Ikeda F. Matsumura and D. M. Benjamin Science 1977 197 497. J. Hurter B. Katsoyannos E. F. Boller and P. Wirz 2.angew. Entomol. 1976,80 50. H. M. Flint R. L. Smith J. G.Pomonis D. E. Forey and B. R. Horn J. Econ. Entomol. 1977,70,547. 82 L. B. Hendry Science 1976 192,143; ibid. 1975 188,59. 83 J. R. Miller T. C. Baker R. T. Cardt and W. L. Roelofs Science 1976,192 140. 84 D. M. Hindenlang and J. K. Wichmann Science 1977,195 86. R. Baker and D. A. Evans secretion of 2-phenylethanol in males of Mamestra configurata has been studied both in uivo and in vitro with crude homogenates and a detailed pathway from phenylalanine has been mapped out. It has been noted that this pheromone is stored in Stobbe's gland as 2-phenethyl-P -glycoside which is hydrolysed on requirement by enzymes contained in hairpencil cap cells.85 Oleic acid appears to be the biosynthetic precursor of n-nonanal a pheromone of the Greater Waxmoth Galleria melonella.86 The production of pheromones in bark beetles by allylic oxidation of un-saturated terpenoid hydrocarbons has attracted much attention.87 The intriguing problem of cantharadin (43) biosynthesis in male Spanish flies has been studied by feeding and successful incorporation of radiolabelled mevalonate farnesol and methyl farnesoate.88 It is interesting to note that the female is unable to produce this defensive material but acquires it by transfer from the male during copulation. 10 Perception of Stimuli The availability of synthetic samples of enantiomerically pure pheromones has much aided studies of olfactory specificity (e.g.refs. 89 and 90). The monitoring of olfactory responses by electroantennography (EAG) and single-cell recording has been applied to investigations of many types of stimulus e.g.host-plant attrac- tant~,~~ cockroach sex attractant^,'^ and Lepidopterous pheromone^.'^ A good correlation between the EAG method and behavioural bioassays was obtained for the repellancy towards Reticulitermes termites of series of quinones and terpenoids of plant origin.94 The roles of thiol and disulphide groups in nerve receptors for u5 J. Weatherston and J. E. Percy Insect Biochem. 1976 6,413; ibid. 1975 5 737. u6 S. P. Schmidt and R. E. Monroe Insect Biochem. 1976,6 377. 87 J. A. A. Renwick P. R. Hughes G. B. Pitman and J. P. Vite J. InsectPhysiol. 1976,22,725;J. A. A. Renwick P. R. Hughes and I. S. Krull Science 1976 191 199; J. M. Brand J. W. Bracke L. N. Britton A.J. Markovetz and S. J. Barras J. Chem. Ecol. 1976 2 195; P. A. Hedin ibid. 1977 3 279. J. R. Sierra W. D. Woggon and H. Schmid Experientia 1976 32 142; Helv. Chim. Acta 1977 60 2288. u9 J. P. Vite D. Klimetzek G. Loskant R. Hedden and K. Mori Naturwiss. 1976,63 582. M. Yamada T. Saito K. Katagiri S. Iwaki and S. Marumo J. Insect Physiol. 1976 22 755. " R. F. Simpson and R. M. McQuilkin Entomol. Exp. Appl. 1976,19 205. 92 H. Washio and C. Nichino J. Insect Physiol. 1976,22 735; C. Nishino H. Washio K. Tsuzuki W. S. Bowers and T. R. Tobin Agric. and Biol. Chem. (Japan) 1977,41,405. 93 T. C. Baker and W. L. Roelofs J. Insect Physiol. 1976 22 1357; Y. Aihara and T. Shibuya ibid. 1977 23 779; T. t.Payne and W. E. Finn ibid. p. 879. 94 M. A. Floyd D.A. Evans and P. E. Howse J. Insect Physiol. 1976 22 697. Biological Chemistry-Part (ii) Insect Chemistry 379 quinone repellants in the American Cockroach have been chemically investi- gated.'' 11 Techniques of Microscale Structure Elucidation The past two years have seen further improvements in the power and sensitivity of both separative and spectroscopic technique^.^^ Attention has been paid to efficient methods of selective extraction of behaviourally active insect chemicals e.g. collection on Porapak Q of volatiles being produced by living insects." This method has particular relevance to cases where pheromones are stored as pre- cursors prior to release. Another useful technique consists of milking pheromone- producing glands with micro-capillaries followed by direct 'solid sample' injection on to a gas chromatograph (g.~.).~' A number of adaptations of gas chromato- graphy to insect chemistry have been reported,98 the most spectacular of which is the monitoring of the response potentials of excised antennae placed post-column in an emergent g.c.gas stream as a selective pheromone dete~tor.~' An efficient splitter-trapping system for micropreparative g.c. has been described,"' and the use of g.c. combined with 13Cn.m.r. spectroscopy has been reported for the separation and determination of purity of geometric isomers of dienes.lo' The enantiomeric composition of several insect pheromone alcohols and acetals has been determined by microscale n.m.r. methods using chiral shift reagents and by formation of diastereisomeric Mosher derivatives."* 12 Behaviour-modifying Chemicals in Pest Control The largest increase in activity in the area of chemical ecology has been observed in the field evaluation of behaviour-modifying chemicals in potential pest control programmes particularly in terms of population survey behaviour disruption and trap baiting.'03 The importance of such factors as enantiomeric puritylo4 and the correct design of traps"' has been emphasized.As expected reports range from significant successes (e.g. ref. 106) to disappointment (e.g.ref. 107). In other cases methods based on chemical ecology offer a comparable alternative to conventional methods.lo8 95 D. M. Norris J. M. Rozental and G. Samberg Cornp. Biochem. Physiof.(C),1977 57 55. 96 J. H. Tumlinson and R. R. Heath J. Chem. Ecol. 1976 2 87. 97 E. D. Morgan and R. C. Tyler J. Chromatog. 1977,134 174. 98 E. Talman P. E. J. Verwiel and A. C. Lakwijk Adu. Mass. Spectrom. Biochem. Med. 1977,2,215; L. M. MacDonald and J. Weatherston J. Chromatog. 1976 118 195. 99 H. Am E. Staedler and S. Rauscher 2.Naturforsch. 1975 30c 11. loo R. Baker J. W. S. Bradshaw D. A. Evans M. D. Higgs and L. J. Wadhams J. Chromatog. Sci. 1976 14,425. H. Disselkoetter K. Eiter W. Karl and D. Wendisch Tetrahedron 1976 32 1591. '02 T. E. Stewart E. L. Plummer L. L. McCandless jun. J. R. West and R. M. Silverstein J. Chem. Ecol. 1977,3,27;E. L. Plummer T. E. Stewart K. Byrne G. T. Pearce and R. M. Silverstein ibid. 1976,2 307. P. A. Hedin Cherntech.1976,6 444. lo4 J. R. Miller K. Mori and W. L. Roelofs J. Znsect Physiof. 1977 23 1447. lo' E. D. M. Macauley and T. Lewis Ecol. Entomol. 1977 2 279. lo6 H. Am B. Deliey M. Baggiolini and P. J. Charmillot Enromol. Exp. Appf. 1976 19 139. Io7 M. D. Proverbs D. M. Logan and J. R.Newton Canad. Entomol. 1975,107 1265. L. K. Gaston R. S. Kaae H. H. Shorey and D. Sellers Science 1977 1% 904; P. H. Westigard and K. L. Graves Canad. Entomol. 1976,108 379. R. Baker and D. A. Evans 13 Synthetic Studies Valuable reviews on the methodology of pheromone ~ynthesis,'~'-~ '' the synthesis of optically active pheromones,' l2 and the synthesis of insect sex attractants on solid phase^^'^?''^ have appeared. Acyclic derivatives.-Two methods which have general applicability have been used in the synthesis of the queen substance 9-oxo-(E)-dec-2-enoic acid.The first involves the sulphenylation and dehydrosulphenylation of esters or ketones,' whereas the key step in the second is an oxidative cleavage which is accompanied by rearrangement of a 2,2-dithiocycloalkan- 1-01(44)(Scheme l).' l6 Conversion of (45) into the queen substance was then achieved by addition of methylmagnesium OHC / C0,Me Reagents i Pb(OAc),; ii MeOH-J2; iii NaI04; iv pyrolysis Scheme 1 chloride followed by Jones oxidation. The queen substance has also been synthesized by a route beginning with reaction of butadiene with diethyl malonate catalysed by palladium acetate and triphenylphosphine.'" In a similar way the same reaction but in the presence of carbon monoxide and t-butyl alcohol yields (46) (Scheme 2).Further carbonylation in presence of octacarbonyldicobalt yields +CO+BU'OH ii iii / CO2H -\ C0,Bu' ' H02C-(46) Reagents i Pd(OAc)z-PPh3; ii Co2(CO)S-MeOH; iii H30+ Scheme 2 log C. A. Henrick Tetrahedron 1977 33 1845. 'lo J. A. Katzenellenbogen Science 1976 194 139. 11' R. Rossi Synthesis 1977 817. '** K. Mori Gendai Kagaku,1976,61 51. 'I3 C. C. Leznoff and T. M. Fyles J.C.S. Chem. Comm. 1976,251. '14 T. M. Fyles C. C. Leznoff and J. Weatherston Canad. J. Chem. 1977,55 1143. '" B. M. Trost T. N. Salzmann and K. Hiroi J. Amer. Chem. SOC.,1976,98,4887. B. M. Trost and K. Hiroi J. Amer. Chem. SOC.1976,98,4313. ''' J. Tsuji K. Masaoka and T. Takahashi Tetrahedron Letters 1977 2267.Biological Chemistry -Part (ii) Insect Chemistry after hydrolysis dec-2-enedioic acid which is one of the components of royal jelly the sole nutrient of queen bee larvae.118 The absolute configuration of (-)-4-methylheptan-3-01 a pheromone of the Smaller European Elm Bark Beetle has been demonstrated to be (3S,4S)."' (R)-(+)-Citronellic acid was converted into a mixture of (3R,4R)-(+)-threo-and (3S,4R)-(+)-erythr0-4-methylheptan-3-01 which were separable by gas chromato- graphy. Manicone (E)-4,6-dimethyloct-4-en-3-one(48) the principal alarm pheromone of certain species of Manica ants has been prepared from a route (Scheme 3) in which the a@-unsaturated carbonyl moiety was introduced by reaction of a 4-chloro-2-pyrazolin-5-one(47) with aqueous sodium hydroxide.lzO Unfortunately Me0,C + LO+&Op+./ 0 HN-NH HN-N Reagents i NHzNHz-EtOH; ii C12-CH2Clz; iii NaOH; iv H30+; v SOC12-C,H,; vi EtzCd-benzene Scheme 3 the opening of the pyrazolinone gave a mixture of 2-and E-isomers and further separation was required.Optically active manicone has been prepared from the titanium tetrachloride-promoted reaction of the appropriately substituted vinyl trimethylsilyl ether and (+)-(2s)-or (-)-(2R)-2-methyIb~tyraldehyde.'~~ J. Tsuji and H. Yasuda J. Organometallic Chem. 1977,131 133. 119 K. Mori Tetrahedron 1977 33 289. I2O P. J. Kocienski J. M. Ansell and R. W. Ostrow I. Org. Chem. 1976 41 3625. K. Banno and T. Mukiayama Chem. Letters 1976 279. 382 R.Baker and D. A. Evans Further studies on the Ips bark beetle pheromones have appeared. Pyrolysis of the esters obtained from 3-methylbut-3-en-1-yl acetate and senecioic anhydride gave predominantly a ketone which on reduction yielded a racemic mixture of 2-methyl-6-methyleneocta-2,7-dien-4-ol, the main aggregation pheromone of Ips paraconfusus.‘22 A small amount of asymmetric induction was found in the forma- tion of 2-methyl-6-methyleneoct-7-en-4-01 and 2-methyl-6-methyleneocta-2,7-dien-4-01 by the coupling of Grignard reagents with the appropriate aldehydes in the presence of ( + )-(2S,3S)-NNN’N’-te trame thyl-2,3 -dime t hoxy bu tane- 1,4- diamine.123 Both enantiomers of the former compound have been synthesized from (S)-(+ )-leucine and its antipode.124 The (I?)-( -)-enantiomer of the dienol has been synthesized from (R)-( + )-glyceraldehyde acetonide obtainable from D-mannito1.12s The natural pheromone was demonstrated to have (S)-configura- tion. The sex pheromone of the female Red Bollworm Moth Diparopsis custanea (E)-dodeca-9,1l-dien-1-01 has been prepared from undec-10-en- 1-01.’~~ The route involved formation of (E)-1 1 -hydroxyundec-2-enal by allylic bromination followed by displacement and oxidation. Finally the synthesis was completed by reaction of methylenetriphenylphosphorane and the aldehyde. A four-step synthesis (Scheme 4) of the sex pheromone of the European Grape Vine Moth Lobesia botrana (E,Z)-dodeca-7,9-dien-l -yl acetate (50) has been reported via a functionalized organoborate.12’ Oct-7-ynyl acetate (49) was pre- pared from hept-1-yne via the acetylene ‘zipper’ reaction of oct-2-yn-1-01 with -/=-.... ,vi-viii Sia,B H H OAc kxi Sia = 3-methyl-2-butyl (50) OAc Reagents i KNH(CH2)3NH*; ii H20; iii Ac2O; iv SiazBH; v,A=-Li; vi 12; vii NaOAc; viii H202-NaOAc; ix Sia2BH; x AcOH; xi H202-NaOAc Scheme 4 lZ2 C. F. Garbers and F. Scott Tetrahedron Letters 1976 1625. S. Karlsen P. Froyen and L. Skattebol Actu Chem. Scand. 1976 B30,664. 124 K. Mori Tetrahedron 1976 32 1101. K. Mori Tetrahedron Letters 1976 1609. 126 J. H. Babler and M. J. Martin J. Org. Chem. 1977,42 1799. 12’ E. Negishi and A. Abramovitch Tetrahedron Letters 1977 411. Biological Chemistry-Part (ii) Insect Chemistry 383 potassium 3-aminopropylamide followed by acetylation.The subsequent reaction depended on the fact that triorganoboranes are much more reactive toward alkynyl-lithiums than the acetoxy-group. The pheromone (50) has also been synthesized by a route involving acid-catalysed ring opening of 1-cyclopropylpent-2-yn-1-01.'~~ Stereoselectivity of the reaction towards the conjugated (E)-enyne was obtained by complexion of the triple bond with octacarbonyldicobalts. (f)-Methyl n-tetradeca-trans-2,4,5-trienoate, produced by the male Dried Bean Beetle Acanthoscelides obtectus has been prepared in which the initial stage was a modified Claisen rearrangement on (51) to produce the allenic ester (52).129A (51) R=octyl (52) Beckmann fragmentation of the oxime (53)to the isomeric nitriles (54)provided the important stage in the synthesis of 3,7-dimethylpentadec-2-~1 acetate the sex pheromone of the Pine Sawfly Neodiprion lecontei (55).13* The preparation of v cR pyridine --+++ p-TsCI ~ CN OAc (53) R = heptyl (54) (55) erythro-3,7-dimethylpentadecan-2-acetate(58),the sex attractant of several species of pine sawflies has been prepared by a method which has more general appli~ability.'~' Beginning with cis-2,3-dimethylcyclohexanone,Baeyer-Villiger oxidation gave the lactone (56) which on reaction with octyllithium yielded the hydroxy-ketone (57).The acetate (58) was then obtained following a Wittig reaction reduction and acetylation. Further stereospecific syntheses have been reported by Bestmann and co-workers.The base sodium bis-trimethylsilylamide'32 has been employed to pro- duce (2)-olefin formation in the Wittig reaction and this procedure was used in the synthesis of (Z,Z)-7,11-and (Z,E)-7,1l-hexadecadienyl acetate the sex pheromone of Pectinophora g~ssypiella.'~~ The synthesis of a series of (E,Z)-conjugated dienes has also been A selective procedure for the general synthesis of conjugated (E,E)-and (E,Z)-dienes involving the reaction of (E)-128 D. Descoins D. Samain B. Lalanne-Cassou and M. Gallois Bull. Chem. SOC. France 1977 941. 129 P. J. Kocienski G. Cernigliaro and G. Felstein J.,Org. Chem. 1977 42 353. P. J. Kocienski and J. M. Ansell J. Org. Chem. 1977 42 1102. G. Magnusson Tetrahedron Letters 1977 2713. 13* H. J. Bestmann W.Stransky and 0.Vostrowsky Chem. Ber. 1976,109.1694. 133 H. J. Bestmann K. H. Koschatsky W. Stransky and 0.Vostrowsky Tetrahedron ktters 1976 353. 134 H. J. Bestmann 0.Vostrowsky H. Paulus W. Billman and W. Stransky Tetrahedron Letters 1977 121. R. Baker and D. A. Evans bii-v OAc Reagents i m-CIC6H4C03H-CH2C12; ii n-CsHl-/Li; iii Ph3P=CHz-HMPA-ether; iv H2-Pd/C- Et0.H; v AqO-pyridine Scheme 5 alkenylalanes (59) readily obtainable via hydroalumination of alkynes with alkenyl halides in the presence of palladium or nickel complexes has also been reported. 135 R' R' +X R1-Z HAIR2 PdLn RZ -R'>=(H /\ or H AIR2 NiLn (59) 1 R' R2 X A magnesium iodide rearrangement of a$-epoxysilane has been used to form p-ketosilanes (60).Subsequent treatment with methyl-lithium and sodium acetate in acetic acid gave (61) which was then transformed into 7-methyl-3-propyldodeca-2(2),6(Z)-dien-l-o1 previously obtained from the codling moth. 13' A synthesis (Scheme 7) of (62) the pheromone of the Parasitic Bean Weevil has involved the reaction of an allenic lithium cuprate with an acetylenic ester.13' Insoluble polymers have been used as supports in the synthesis of (2)-dodec-7- enyl (Z)-tetradec-g-enyl and (2)-tetradec- 11-enyl Stereoselective synthesis of the isomeric pentadeca-5,lO-dienals has been re~0rted.l~~ The (S)-enantiomers of (2)-and (E)-14-methylhexadec-8-en-1-01and the corresponding aldehydes which are sex pheromone components of dermestid beetles have been ~ynthesized.'~' In this work a new method for the stereospecific lithium aluminium hydride reduction of o-alkynols to the corresponding (E)-alkenols is described.14' S. Baba and E. Negishi J. Amer. Chem. SOC.,1976 98 6729. M. Obayashi K. Utirnoto and H. Nozaki Tetrahedron Letters 1977 1807. D. Michelot and G. Linstrumelle Tetrahedron Letters 1976 275. 13' C. C. Leznoff T. M. Fyles and J. Weatherston Canad. J. Chem. 1977 55,4135. G. Ohloff C. Vial F. Naf and M. Pawlak Helv. Chim. Acta 1977,60 1161. R.Rossi and A. Carpita Tetrahedron 1977 33 2447. 141 R.Rossi and A. Carpita Synthesis 1977 561. Biological Chemistry-Part (ii) Insect Chemistry H. SiMe SiMe I -=-SiMe -=-SiMe OH Reagents i MgI2-ether; ii MeLi; iii AcONa-AcOH Scheme 6 Reagents i BuLi; ii n-CgH17Br; iii BuLi; iv CuI; v r-C02Me Scheme 7 The sex pheromone of the Gypsy Moth (Z)-7,8-epoxy-2-rnethyloctadecane (65) has been synthesized by a Wittig reaction in presence of the base sodium bis- trimethyl~ilylarnide.'~~ The stereospecific reaction of (63) with the vinylsilane (64) has been used in the synthesis of (65)(Scheme 8).143 Both enantiomers of this I OAc li ii Reagents i H+; ii m-CIC6H4C03H Scheme 8 14' H.J. Bestrnann 0.Vostrowsky and W. Stransky Chem. Ber. 1976,109 3375. W. Mychajlowskij and T. H. Chan Tetrahedron Letters 1976 4439. R. Baker and D. A. Evans compound have been synthesized from the (2S,3S)-threo configuration of L-( +)-tartaric and the (7R,8S)-enantiomer has also been prepared from 1-menthyltoluene-p-sulphinate.145Further studies on the olefin metathesis reaction have appeared.The pheromones of the Housefly Face Fly and Gypsy Moth have been formed from suitable alkenes with homogeneous and heterogeneous cata- lyst~.~~~ A synthesis of muscalure (2)-9-tricosene in which the first step was reaction of an ester of oleic acid with pentylmagnesium bromide has been described.14’ Two interesting syntheses of (2)-6-heneicosen- 11-one (68) the sex pheromone of the Douglas Fir Tussock Moth both involving tosylhydrazone fragmentation have been reported. 148*149 In one of these (Scheme 9) the epoxide (66) yields the acetylenic ketone (67) which is then converted into (68).14* The synthesis of racemic150 and optically active stere~isomers~~~ of 3,ll -dimethylnonacosan-2-one and 29-hydroxy-3,1 l-dimethylnonacosan-2-one,152.’53 two compounds isolated from virgin females of BZattela germanica have been reported.Phase-transfer methylation of benzyl3-oxobutanoate as a route to 3-methyl-2-alkanones has also been shown to be valuable for the synthesis of these two 0 (68) Reagents i n-CloH21MgBr; ii H30+; iii H202-NaOH-MeOH; iv p-TsNHNH2; v H2-Pd/BaS04 Scheme 9 144 K. Mori T. Takigawa and M. Matsui Tetrahedron Letters 1976 3953. ’*’ D. G. Farnum T. Veysoglu A. M. Cardt B. Duhl-Emswiler T. A. Pancoast T. J. Reifz and R. T. CardC Tetrahedron Letters 1977 4009. 146 F. W. Kuepper and R. Streck 2.Naturforch. 1976 31b 1256. 14’ K. Abe T. Yamasaki N. Nakamura and T. Sakan Bull.Chem. SOC. Japan 1977,50,2792. 14’ P. J. Kocienski and G. J. Cernigliaro J. Org. Chem. 1976,41 2927. 14’ K. Mori M. Uchida and M. Matsui Tetrahedron 1977 33 385. lJ0 L. D. Rosenblum R. J. Anderson and C. A. Henrick Tetrahedron Letters 1976,419. lS1 C. Conti A. Niccoli and R. Rossi Chimica e Industria 1976,58 877. lS2 A. W. Burgstahler L. 0.Weigel M. E. Sanders C. G. Schaefer W. J. Bell and S. B. Vuturo J. Org. Chem. 1977,42,566. lS3 R. Nishida T. Sato and Y. Kuwahara Agric. and Biol. Chem. (Japan) 1976,40 1407. A. W. Burgstahler M. E. Sanders C. G. Schaefer and L. 0.Weigel Synthesis 1977,405. Biological Chemistry -Part (ii) Insect Chemistry Alicyclic Derivatives.-Full details of the synthesis of optically active grandisol (71) one of the four synergistic components of the male Boll Weevil pheromone has been p~blished.'~' Photolysis of (69) obtainable in a series of steps from (-)-P -pinene gave (70) which on decarbonylation using chlorotris(tri-pheny1phosphine)rhodium gave grandisol acetate and subsequently (+)-grandisol (+)-(lR,2S)-l-methyl-l-(2-hydroxyethyl)-2-isopropenylcyclobutane.A process of geminal alkylation involving 1-lithiocyclopropyl sulphide has also been used in a synthesis of grandis01.'~~ H (69) (70) (71) A two-step synthesis of a mixture of the two (3,3-dimethylcyclo-hexy1idine)acetaldehydes (73) two other components of the boll weevil pheromone has been re~0rted.I~~ In this Vilsmeier formylation of isophorone afforded (3-chloro-5,5-dimethylcyclohex-2-enylidene)ace~aldehyde (72) in 80% yield.Catalytic hydrogenation of (72) over palladium on charcoal poisoned with sulphur and quinoline gave a 2 :1 mixture of the E/Z-isomers of (73). Treatment (72) (73) of the reaction product with a catalytic amount of toluene-p-sulphonic acid yielded a 1:1 mixture of stereoisomers. These two compounds together with the other cyclohexyl component (77) have also been prepared from 3-methylcyclohex-2- enone by way of (74)-(76) (Scheme One problem in this synthesis is that (77) the desired alcohol is obtained as a 1 1 mixture with (78); a difficult separation is necessary here. The formation of a P-unsaturated aldehydes by the bishomologation of ketones has also been applied to the synthesis of the aldehyde components of the pheromone mixture.'59 Syntheses of endo- and exo-brevicomin have attracted much attention.Both of them were synthesized by a route involving reaction of the tosylhydrazone formed from the epoxide of 1-ethyl-2-methylcyclohex-l-enone.'60The acetylenic ketone (80)obtained from this reaction has also been obtained by the reaction of (79) with methyl-lithium. The acetylenic ketone was reduced to the cis-olefin (8l) P. D. Hobbs and P. D. Magnus J. Arner. Chem. SOC.,1976 98,4594. B. M. Trost D. E. Keeley H. C. Arndt and M. J. Bogdanowicz J. Amer. Chem. Soc. 1977,99,3088. P. C. Traas H. Boelens and H. J. Takken Rec. Truu. chim. 1976,95 308. lS8 S. W. Pelletier and N. V. Mody J. Org. Chem. 1976 41 1069. lS9 J. H. Babler and J. M. Coghlan Synth. Comm. 1976,6 469.160 P. J. Kocienski and R. W. Ostrow J. Org. Chem. 1976 41 398. J. L. Coke H. J. Williams and S. Natarajan J. Org. Chern. 1977 42 2380. R. Baker and D. A. Evans Reagents i MeZCuLi; ii L~CECH-NH~(CH~)~NH~; iii Ac20-H+; iv 80% AcOH-Ag2C03; v H20; vi 9-BBN or NaBH4 Scheme 10 whence epoxidation and thermolysis gave exo-brevicomin (82) the pheromone from Dendroctonus brevicornis (Scheme 11). The selective irradiation of the Reagents i PCI3; ii MeLi; iii heat; iv m-CIC6H4C03H Scheme 11 carbonyl group of 2-propionyl-6-methyl-2,3-dihydro-4H-pyranhas also been shown to be after hydrogenation a selective and elegant route to exo-brevi- comin.162A further synthesis of (-)-(lS,7S)-exo-brevicornin is rep0~ted.I~~ endo-Brevicomin (83),a pheromone inhibitor has been synthesized by a palladium(I1)- catalysed intramolecular cyclization of a terminal olefin containing a suitably located vicinal diol group (84).'64 162 D.Chaquin J. P. Morizur and J. Kossanyi J. Amer. Chem. SOC.,1977,99 903. H. H. Meyer Annalen 1977 732. '64 N. T. Byrom R. Grigg and B. Kongkathip J.C.S. Chem. Comm. 1976 216. Biological Chemistry-Part (ii) Insect Chemistry 389 &-PdC12-CuC12 OH (83) (84) Both enantiomers of frontalin have been synthesized from the ketone (85) derivable from methyl a-D-glucopyranoside. 165 Thus (lR,SS)-frontalin (90) was prepared through the intermediate compounds (86)-(89). HO (86) Bn =PhCH2 (87) 1 AcO fo\ i,Ph3P CHZOH t a-Multistriatin (92) one of the compounds of the aggregation pheromone of Scolytus multistriutus has been synthesized from (9l) which was available from (Z)-b~t-2-ene-1,4-diol.~~~ A similar route except that (91) was prepared from O# (91) (I?)-( +)-glyceraldehyde obtainable from D-mannitol established the absolute stereochemistry of the natural pheromone to be (1S,2R,4S,5R).'67 The same conclusion was reached as a result of a synthesis beginning with (S)-(+)-2-methyl-but-3-enoic acid.'68 a-Multistriatin has also been synthesized by a route beginning with (+)-(3R)-citronellol although the final product was a mixture of a-y-isomers and gas-chromatographic separation was required.16' The oxidation of pinene was used to prepare optically pure (+)-trans-verbenol the pheromone of Dendroctonus bark beet1es.l" Both enantiomers of cis-verbenol 16' D.R. Hicks and-B. Fraser-Reid J.C.S. Chem. Comm. 1976 869. '66 W. J. Elliot and J. Fried J. Org. Chem. 1976 41 2475. 16' K. Mori Tetrahedron 1976 32 1979. 16' G. T. Pearce W. E. Gore and R. M. Silverstein J. Org. Chem. 1976,41 2797. G. J. Cernigliaro and P. J. Kocienski J. Org. Chem. 1977,42 3622. ''O K. Mori Agric. and Biol. Chem. (Japan) 1976,40,415. R. Baker and D. A.Evans were synthesized from (+)-and (-)-verbenone.171 It was further pointed out that the pheromone of the Ips bark beetle should be described as (lS,4S,SS)-pin-2-en- 4-01 rather than (+)-cis-verbenol since the sign of rotation depends on the solvent enclosed. A general synthesis of optically active 4-alkyl (or 4-alkenyl)-y-lactones from commercially available enantiomers of glutamic acid is reported.172 Both enan- tiomers of S-n-hexadecalactone the pheromone suggested to be responsible for social behaviour of the queens and workers of Vespa orientalis have been prepared from (R)-(+) and (S)-(-)-1,2-epo~ytetradecane.l~~ The epoxides were prepared by resolution of 1-dimethylaminotridecan-2-01 with the enantiomers of dibenzoyl-tartaric acid followed by Hofmann elimination. A termiticidal norsesquiterpenoid dl-chamaecynone (93) has been prepared by a route involving a Diels-Alder reaction of (94) and (95).174 A defensive secretion of the termite Arniterrnes evuncifer 4,ll -epoxy-cis-eudesmane (99) has been synthesized stereospecifically from (-)-carvone (96) in which the key steps were annulation to (97) and oxymercuration to (98).17' Other reported synthesis include those of 2-deoxyecdy~ones'~~ and dl-ne~cembrene.'~~ 0 OH OH (97) 1 17' K.Mori N. Mizumachi and M. Matsui Agric. and Biol.Chem. (Japan) 1976 40 1611. "* U. Ravid and R. M. Silverstein Tetrahedron Letters 1977 423. 173 J. L. Coke and A. B. Richon J. Org. Chem. 1976,41,3516. 174 T. Harayama H. Cho and Y. Inubushi Tetrahedron Letters 1977 3273. 17' R. Baker D. A. Evans and P. McDowell J.C.S. Chem. Comm. 1977 111. 176 J. F. Kinnear M. D. Martin D. H.S. Horn,E. J. Middleton J. S. Wilkie M. N. Galbraith and R. I. Willing Austral. J. Chem. 1976 29 1815. 177 Y. Kitahara T. Kato and T. Kobayashi Chem. Letters 1976 3 219. Biological Chemistry-Part (ii) Insect Chemistry A synthesis of furanoterpenoids involving a 1,4-~ycloaddition reaction of singlet oxygen appears to be generally useful.17' The 2,5-dialkylpyrrolidines which are constituents of the South African Fire Ant Solenopsispunctuticeps have been pre- pared by stepwise alkylation of 2-lithio-1-nitrosopyrrolidines 179 and by photolysis of the appropriate N-chIor~amines.~~ 17' K. Kondo and M. Matsumoto Tetrahedron Letters 1976 390. R. R. Fraser and S. Passannanti Synthesis 1976 540.

ISSN:0069-3030    

DOI:10.1039/OC9777400367

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

14 Biological Chemistry Part (iii) Tetrapyrroles and their Biosynthesis By D. G. BUCKLEY Chemistry Department Queen Mary College Mile End Road London El 4NS 1 Introduction In the three years since porphyrins and related compounds were last reviewed in Annual Reports,’ a great deal of new work has been published much of which relates to the biosynthesis of porphyrins chlorins and corrins and to details of their biological activity. Most of this work relates directly to results published since the late 1960’s and where appropriate a brief summary of this earlier work will be included.* The publication of the authorititative ‘Porphyrins and Metallopor- phyrins’ edited by K. M. Smith,* and based on Falk’s original was most welcome as was the appearance of a full account4 of the important Royal Society discussion on the biosynthesis of porphyrins chlorophyll and vitamin BI2held in London in February 1975.The informal ‘Tetrapyrrole Discussion Group’ has been founded recently as a result of the increased activity in this area.? CO,H 2 Me Me I I CO H CO H (1) Porphyrin (2) Cobyrinic acid * The period on which this review is based is January 1975 to March 1978. t Hon. Secretary/Treasurer Dr. S. B. Brown Department of Biochemistry University of Leeds 9 Hyde Terrace Leeds LS2 9LS U.K. ’ A. H. Jackson Ann. Reports (B),1974,71 519 ‘Porphyrins and Metalloporphyrins’ ed. K. M. Smith Elsevier Amsterdam 1975. J. E. Falk ‘Porphyrins and Metalloporphyrins’ Elsevier Amsterdam 1964. Phil. Trans. Roy.SOC.,1976 B273,pp. 75-357. 392 Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis Both porphyrins and chlorins are based on the porphyrin (porphin) ring system (l),while the cobalamins are corrin derivatives e.g. cobyrinic acid (2). The newer and more systematic numbering system will be used in this article; the older descriptions for the four meso carbon atoms (a,p 7 and 6) are given for reference in (1). 2 Biosynthesis of Tetrapyrroles General Remarkable progress has been made in our understanding of the biosynthesis of the haems chlorophylls and corrins over the past thirty years and a summary of what was known’ at the end of 1974 is given in Scheme 1. Porphobilinogen (PBG) ALA J e- Me (4) Copro’gen-11I (3) Uro’gen-111 >)< 1 The Cobalamins (5) Proto’gen-IX (6) Protoporphyrin-IX Here and elsewhere A = CH2C02H Y kg P = CH2CH,C02H The Haems The Chlorophylls Scheme 1 Reviewed by A.R. Battersby and E. McDonald in ref. 2 pp. 61-122. 394 D. G. Buckley normally derived from glycine and succinyl coenzyme A by way of 5-amino-laevulinic acid (ALA) is condensed to give uroporphyrinogen-I11 (abbreviated to “uro’gen-111”) (3) as the next discrete (i.e. detectable) intermediate. Modification of the side-chains then occurs to give protoporphyrinogen-IX (“proto’gen-IX”) (5) by way of coproporphyrinogen-I11 (“copro’gen-111”) (4); oxidation of the porphy- rinogen system follows to give protoporphyrin-IX (6) which either leads directly to the iron-containing haems or else to the chlorophylls after insertion of magnesium followed by further modification.The pathway to the cobalamins is thought to branch at the uro’gen-I11 stage; one of the bridging methylene groups in uro’gen- I11 (3) must be removed to give the corrin ring system cf. (2). Re~ently,~ efforts have been directed towards elucidating the details of various steps in the above biosynthetic pathway; for clarity this work will be divided into four main sections (a) the specific formation of uro’gen-111; (b) modification of side-chains and subsequent aromatization of protoporphyrin-IX; (c) the iron and magnesium branches; and (d)the biosynthesis of vitamin B,*. 3 Biosynthesis of Uro’gen-111 the ‘Type-111 Problem’ Early work established the crucial role of PBG in the biosynthesis of protohaem and in turn PBG was shown to be synthesized from glycine and succinyl coenzyme A by way of ALA.’ Recent work6 has shown that ALA synthetase catalyses the condensation of glycine and succinyl-CoA by specific removal of the pro-2R- hydrogen of glycine; the pro-2s-hydrogen of glycine was shown to occupy the pro-5s-position in the derived ALA (Scheme 2).Further have now revealed the fate of the two hydrogen atoms at C-5 in ALA during its conversion into PBG by ALA dehydratase. C-5 of one ALA molecule provides the aminomethyl side-chain of PBG and the substituents at C-5 are incorporated intact. Position 2 of PBG is derived from C-5 of the second ALA molecule; specific loss of the pro-5R-hydrogen of ALA occurs during the aroma- tization step to yield PBG that has the pro-5s-hydrogen of ALA at C-2 (Scheme 2).6-8 These results suggest that the removal of the pro-R-hydrogen atoms from an intermediate such as (7)occurs while the species is enzyme-bound and not after its release into the medium [(7)+ (7a) +PBG] as is implicated in the otherwise excellent mechanistic sequence proposed earlier by Nandi and Shemin.’ The pioneering studies of Shemin Granich Bogorad Neuberger and Riming- ton5 established that the co-operative action of two enzymes porphobilinogen deaminase (‘deaminase’) and uroporphyrinogen-I11 cosynthetase (‘cosynthetase’) was required to catalyse the conversion of faur molecules of the monopyrrole PBG into uro’gen-111 (3) and ammonia (Scheme 3).In the absence of cosynthetase deaminase catalyses the conversion of PBG into uro’gen-I (8) the isomer that would be expected from single head-to-tail combination of four PBG units. However uro’gen-I (8) is not transformed into uro’gen-111 (3) by cosynthetase alone nor by the complete deaminase-cosynthetase system. These results sum- ‘M. M. Abboud P. M. Jordan and M. Akhtar J.C.S. Chem. Comm. 1974,643. ’ M. Akhtar M. M. Abboud G. Barnard P. Jordan and 2. Zaman in ref. 4 pp. 117-136. a M. M. Abboud and M. Akhtar J.C.S. Chem. Comm. 1976 1007. D. L. Nandi and D. Shemin J. Biol. Chem. 1968,243 1236. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis C02H Hs synthetase 0 [2,2-3H2]glycine (5S)-[5-3H1]ALA H N -H,C 10 H H2N (11S)-[2,1 l-3H2]PBG + Enz-NH2 H,N-H,C H H Scheme 2 deaminase yinaseit;;ynthetase a,on/ A 'a: +4NH3 + :a A +4NH3 P (8) Uro'gen-I (3) Uro'gen-I11 Scheme 3 396 D.G. Buckley marize the 'type-I11 problem' how does the complete enzyme system bring about the molecular rearrangement required to produce the unexpecfed type-111 isomer and what are the intermediates in this intriguing transformation? The Nature of the Rearrangement.-Until 1973 there were no answers to these questions although some 25 hypothetical mechanisms had been prop~sed.~,~~ However in a series of 13Cn.m.r. experiments," Battersby and McDonald were able to deduce what happened during the biosynthesis of uro'gen-111 (3) from PBG i.e.they were able to deduce the origin of each of the carbon atoms which make up the porphyrin macrocycle. Full details af this work have now been published" and are summarized below. [2,1 l-'3C2]Porphobilinogen (9) was prepared from 90 atom YO '3C-labelled ALA (1O),I3 using the enzyme ALA-dehydratase. No dilutions were made throughout so 81% of the PBG molecules were doubly labelled as in (9). This PBG (1 part) was diluted with normal unenriched PBG (4parts) and the resultant PBG sample was incubated with a PBG-free enzyme system from the alga Euglena gracilis. The product was protoporphyrin-IX [Iabelled (6)]; this was formed because the biological system contained all the enzymes necessary to effect the conversion of the uro'gen-111 [labelled (3)] as it was formed through the steps in Scheme 1 as far as [labelled (6)].After I3C n.m.r. analysis this product was converted chemically into the labelled diketone (1 1) as shown in Scheme 4. (9) Reagents i Enzyme preparation from E. gracilis; ii HBr-HOAc HzO; iii CH2N2; iv Na2Cr207-HZS04-HZO. Scheme 4 lo Ref. 5 pp. 85-87. See also E. Margoliash Ann. Rev. Biochem. 1961,30,551;J. H. Matheson and A. H. Corwin J. Amer. Chem. SOC.,1961,83 135; E. Bullock Nature 1965 205 70; E. B. C. Llambias and A. M. del C. Batlle Biochem. J. 1971,121,327;R. Radmer and L. Bogorad Biochemistry 1972 11 904. A. R. Battersby E. Hunt and E. McDonald J.C.S. Chem. Comm. 1973,442. l2 A. R. Battersby G. L. Hodgson E. Hunt E. McDonald and J. Saunders J.C.S. Perkin I 1976 273.l3 A. R. Battersby E. Hunt E. McDonald and J. Moron J.C.S. Perkin I 1973 2918. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis 397 The low-field part of the 'H-decoupled 13C n.m.r. spectrum of the labelled protoporphyrin-IX (6) contained signals from the meso-carbon atoms C-5 C-10 and C-20 as 5.5Hz doublets while that for C-15 was a 72Hz doublet. The chemical shifts for C-5 C-10 C-15 and C-20 were assigned14 by rational total synthesis of (6) that was specifically labelled at C-10 C-15 and C-20 respectively. Also the couplings of 72 Hz and 5.5 Hz were proved to correspond respectively to direct coupling of two adjacent 13Catoms and to I3C-l3Ccoupling through three bonds as in Scheme 5 by the unambiguous preparation12 of the appropriate doubly labelled porphyrins.The spectrum of the derived diketone (ll) in which the 13C n.m.r. signals for the four meso-carbon atoms are even more clearly differentiated showed similar features. Thus it was clearly established that the major components in the labelled sample of protoporphyrin-IX (6) that was derived from the incubation experiment were the four doubly labelled species shown in Scheme 5. , Me\ O ' U/ Me ii ii C0,Me C0,Me C0,Me C0,Me 5.5 Hz 5.5 Hz C0,Me C0,Me C0,Me C0,Me 5.5 Hz 72 Hz Scheme 5 Exactly the same conclusion was derived from studies" of the incorporation of the same diluted [2,11-'3C,]PBG (9) into protoporphyrin-IX [labelled (6)] by a mixed enzyme preparation from chicken blood and beef mitochondria.Further- more it has been shown15 that during enzymic conversion of uro'gen-I11 (3) into l4 A. R. Battersby G. L. Hodgson M. Ihara E. McDonald and J. Saunders J.C.S. Perkin I 1973 2923; A. R. Battersby M. Ihara E. McDonald J. Saunders and R. J. Wells ibid. 1976 283. 15 B. Franck D. Gantz F.-P. Montforts and F. Schmidtchen Angew. Chem. Internat. Edn. 1972 11 421; A. R. Battersby J. Staunton and R. H. Wightman J.C.S. Chem. Comm. 1972 1118; A. R. Battersby E. McDonald J. R. Redfern J. Staunton and R. H. Wightman J.C.S. Perkin I 1976 266. 398 D. G. Buckley protoporphyrin-IX (6) (see Scheme l) the macrocycle remains intact and unscrambled. All the results obtained for protoporphyrin-IX (6) therefore hold good for uro’gen-I11 (3).From these experiments the nature of the rearrangement process by which type-I11 porphyrins are biosynthesized has been defined and it is characterized by the following features (a) the three PBG units which form ring A and its attached C-20 bridge ring B and the C-5 bridge and ring c with its C-10 bridge are all incorporated intact without rearrangement; (b),the PBG unit which forms ring D is built in with rearrangement which is intramolecular with respect to that PBG unit; and (c) the rearranged carbon atom forms the bridge at C-15. It is of considerable interest that exactly the same features characterize the biosynthetic process which generates type-I11 porphyrins in such widely different organisms as an alga (Euglena gracilis) a chicken and a bacterium (Propionibacterium sher- manii).l6 The Role of Cosynthetase Timing of the Rearrangement.-The known’ deaminase-catalysed conversion of PBG into uro’gen-I (8) is usually con~idered~~’*~* to occur by simple head-to-tail combination of four PBG units without rearrangement.Recent studiesI6 with [2,11-13C2]PBG(9) and a purified preparation of deaminase from E. gracih have confirmed this view; 13C n.m.r. analysis of the recovered I3C-labelled uroporphyrin-I octamethyl ester showed that each of the four PBG units had been incorporated intact into uro’gen-I (8). A plausible sequence for the interaction of PBG with deaminase is given in Scheme 6. The fact that deaminase alone catalyses head-to-tail coupling of four PBG units to produce uro’gen-I (8) while deaminase and cosynthetase together catalyse the formation of uro’gen-I11 (3) from three intact PBG units and one intramolecularly rearranged unit suggests that cosynthetase must bring about this rearrangement either by operating on an intermediate produced by deaminase or by modifying the way in which deaminase brings about one of the coupling steps.Cosynthetase might operate at any stage in the overall process i.e. at the monopyrrole dipyrrole tripyrrole or tetrapyrrole level and it should be possible to make a distinction by testing the hypothetical intermediates (12)-(15) of Scheme 6 (and rearranged isomers) as precursors of uro’gen-I11 (3). Early work5,” suggested that rearrangement does not occur as the first step although incorporation studies have not been reported.Dipyrrolic Intermediates in Uro’gen-I11 Biosynthesis.-Pyrromethanes e.g. (16) have been prepared 18-20 in several laboratories and tested for incorporation into type-XI1 porphyrins in the presence of the deaminase-cosynthetase system. The l6 A. R. Battersby E. McDonald R. Hollenstein and D. C. Williams unpublished work Cambridge 1976; personal communication. l7 A. T. Carpenter and J. J. Scott Biochem. Biophys. Ada 1961,52 195. A. R. Battersby D. A. Evans K. H. Gibson E. McDonald and L. N. Nixon J.C.S. Perkin I 1973 1546; A. R. Battersby J. F. Beck and E. McDonald ibid. 1974 160. l9 B. Frydman and R. B. Frydman Accounts Chem. Res. 1975,8 201. 2o e.g. J. Bausch and G. Miiller Enzyme 1974,17,47;J. M. Osgerby J. Pluscec Y. C.Kim F. Boyer N. Stojanac H. D. Mah and S. F. MacDonald Canad. J. Chem. 1972,50 2652. 399 Biological Chemistry-Part (iii) Tetrapyrroles and their Biosynthesis +-i-=7-NH3 PBG uroporphyrinogen-I (8) NH3 or Jh X =NHz or group X group of deaminase Scheme 6 on enzyme initial results of such were confusing and led to some disagreement between the groups at Buenos Aire~,’~.’~ and (later) Yale.24 Cambridge,5*zz*z3 All researches on the enzymic incorporation of PBG and pyrromethanes into porphyrinogens are complicated by concomitant non -enzymic conversion of sub-strates into porphyrinogens (often accompanied by some prior rea~rangement),’~ and this results in a troublesome blank. This is a major difficulty encountered by all workers in the area and undoubtedly is an important factor in the differences in results indicated above.The interested non-expert must remember that a I4C-labelled precursor has not been proved to be incorporated until (a)the precursor is shown to be chemically (including isomerically) pure; (b)the isolated products are proved to be chemically (including isomerically) and radiochemically pure; and (c) the incorporations observed are proved to be specific and the site(s) of labelling are determined. Recent results from the Cambridge groupz6 with both 13C- and 14C-labelled aminomethylpyrromethanes and with 13C-labelled bilanes (see later) have B. Frydman R. B. Frydman A. Valasinas E. S. Levy and G. Feinstein in ref. 4 pp. 137-160. z2 A. R. Battersby D. A. Evans K.H. Gibson E. McDonald L. N. Mander and J. Moron J.C.S. Chem. Comm. 1973 768. 23 A. R. Battersby and E. McDonald in ref. 4 pp. 161-180. 24 A. I. Scott K. S. Ho M. Kajiwara and T. Takahashi J. Arner. Chem. Soc. 1976,98 1589. ’’G. W. Kenner A. H. Jackson and D. Warburton J. Chem. SOC.,1965 1328. 26 (a) Reviewed by A. R. Battersby in the Paul Karrer Lecture University of Zurich (July 1977) Experientia 1978,34 1; (6)See also A. R. Battersby and E. McDonald Accounts Chem. Res. 1978 11,in the press. 400 D. G. Buckley clarified the role of pyrromethanes in uro'gen-I11 (3) biosynthesis and their results are presented first. Preliminary had suggested that only the pyrromethane AP.AP (16) was involved in uro'gen-I11 biosynthesis. When the intact enzyme systems from E.grucilis or avian erythrocytes were used radioactivity was found in the isolated protoporphyrin-IX (6) from ['4C]AP.AP (16) (range 1.6-9.0% with duck eryth- rocytes and 0.2-0.5% with E. grucilis)and from [14C]PA.AP (18) (range 0.06- 0.12% from duck erythrocytes and 0.01-0.015% from E. gracilis); even lower maximum incorporations were obtained from incorporation studies with ['4C]AP.PA (17) (0.05%) and [14C]PA.PA (19) (0.09°/~).The incorporations of the rearranged pyrromethanes (17) (18) and (19) were so low that the labelling pattern could not be checked by degradation. AflAm NH HN /' NH HN /A H,NJ H,NJ (16) AP.AP (17) AP.PA p&-PJNH HN /' P mNHHN / A H2N J H,NJ (18) PA.AP (19) PA.PA In contrast (Scheme 7) the relatively high level of incorporation of radioactivity from the unrearranged isomer (16a) into the isolated protoporphyrin-IX dimethyl ester (21a) and haemin ester (20a) using the enzyme system from duck erythrocytes allowed oxidative degradation of the latter to the four biliverdins-IXa -IX& -IXy and -1XS [the IXa isomer (22) is illustrated in Scheme 7].27 The haemin ester isolated after incubation of [14C]AP.AP (16a) with enzymes but without PBG was degraded to the four biliverdins which showed that the I4C activity of the haemin ester (20) was distributed equally between C-5 and C-15.It followed that the [14C]AP.AP (16a) had been specifically incorporated into uro'gen-I11 (3) to label C-5 and C-15 equally.22,28 This specific incorporation of AP.AP (16) without PBG into uro'gen-I11 (3) was also found2* with the enzymes from E.grucilis. The initially formed uro'gen-I11 (3) was again enzymically converted in situ into protoporphyrin-IX (6); incubation of [bridge-methylene-'3C]AP.AP (16b) led to recovery of [5,15-'3C2]protoporphyrin-IX ester (21b) whereas [~minomethylene-'~C]AP.AP (16c) gave [10,20-'3C2]pro- toporphyrin-IX ester (21c) as in Scheme 7. The sites of labelling were read directly from the I3Cn.m.r. spectra using the ear!ier unambiguous assignment^.'^ The Frydmans have that the above incorporations with AP.AP (16) may not be leading to protoporphyrin-IX (6) as described but to an unnatural '' R. Bonnett and A. F. McDonagh Chem. Comm. 1970,237. A. R. Battersby Special Lecture 23rd Znternat.Congr. Pure Appl. Chem. 1971,5 1. 29 R. B. Frydman and B. Frydman F.E.B.S. Letters 1975 52 317. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis 401 enzymes b (16a) 14Cat * (16b) llIC at 0 (16c) Cat ji!kZEtion (20)X = Fe"'-CI (20a) 14cat * (21) -P X t = H H (21a) 14cat * (21b) EC at (21c) Cat rn Uro'gen-IV [plus isomers] [enzymes \ \ COzH CO,H C0,Me C0,Me (23) LJ$abelled (22) Biliverdin-IXa ester (23a) Cat * 14cat * (23b) ll:C at 0 [plus IXp IXy and 1x6 isomers] (23c) Cat Scheme 7 isomer protoporphyrin-XI11 (23). Their view was based on the known chemical formation (by rearrangement) of some uro'gen-IV from AP.AP (16),22,29 which could then be converted enzymically via copro'gen-IV into protoporphyrin-XI11 (23) (Scheme 7); the terminal enzymes of protoporphyrin-IX (6) biosynthesis (see Scheme 1)are known5 to act on these unnatural isomers.This suggestion cannot be correct. It is clear that the product obtained by the Cambridge group is unquestionably protoporphyrin-IX (6) for the following reasons. First the recently proved structure of protoporphyrin-XI11 (23)30has a plane of symmetry which renders C-10 and C-20 equivalent [cf. (21)]; the four 30 H.M. G. AI-Hazimi A. H. Jackson D. J. Ryder G. H. Elder and S. G. Smith J.C.S. Chern. Cornrn. 1976 188; L. Mombelli E. McDonald and A. R. Battersby Tetrahedron Letters 1976 1037; G. Buldain J. Hurst R. B. Frydman and B. Frydman J. Org. Chem. 1977,42 2953. 402 D. G. Buckley different 13C n.m.r.signals observedZ2 from the bridge carbon atoms of the labelled biosynthetic products (2 lb) and (21c) could not have arisen from protoporphyrin- XI11 (23). Second the haemin ester derived from a protoporphyrin of structure (23) could not be degraded27 to any of the known biliverdin-IX isomers obtained22’28on degradation of the protoporphyrin recovered from the incubation experiments (see Scheme 7). Third protoporphyrin-IX and protoporphyrin-XI11 dimethyl esters are separable by h.p.l.c. and the product from the above enzymic experiments was distinguished in this ‘kay from isomer XI11 and identified with isomer IXZ6’ These experiments prove conclusively that two molecules of unrearranged AP.AP (16) can combine and rearrange in a highly specific manner to generate uro’gen-I11 (3) in the presence of the deaminase-cosynthetase system.The prob- lem of determining the extent of chemical versus enzymic formation of uro’gen-I11 (3) in the incubation experiment26 was solved by the development of methods for isolating the derived uroporphyrins from highly reactive pyrr~methanes~’ and for quantitative ~eparation~~ of the recovered porpbyrin isomers. The isolated mixture of uroporphyrin esters was decarboxylated with hot to the cor- responding mixture of coproporphyrin isomers; a two-stage h.p.1.c. separation of the tetramethyl esters allowed the four coproporphyrin isomers to be collected and assayed.32 Incubation3’of [14C]AP.AP (16a) at pH 7.2 for 16h without enzyme gave a ca. 30% yield of uroporphyrins having the isomer composition shown in Table 1.When a strictly parallel experiment was run but with the addition of purified deaminase-cosynthetase from E. gracilis the isomer ratio was dramatically altered (see Table l) type-I11 formation being vastly increased (3’/0+54~/0) at the expense of type-I formation (68%+15%). The competing chemical formation of the type-IV isomer was essentially unaffected by deaminase-cosynthetase. Table 1 Radioactivity of the uro’gen isomers formed from AP.AP (16a) Uro’gens formed (“10of total) ~ r 7 Type-I Type-II Type-111 Typ-IV Blank run 68*2 1*L 3*2 28*2 Enzyme run 15*1 2*1 54*2 29*2 In addition the doubly 13C2-labelled form of AP.AP (16d) synthesized18*20 from [2,ll- 13C2]PBG (9) was with purified deaminase-cosynthetase and then worked up as in the 14Cseries31 to give coproporphyrin-111 tetramethyl ester.The 13Cn.m.r. signal that arises unambiguously from C-15 was a 72 Hz doublet centred on a smaller singlet. It followed that the labelling pattern around C-15 was that shown in Scheme 8 for uro’gen-IIIC(3d) and (3e)] and the signal from C-5 was consistent with the illustrated arrangement around ring B. The ratio of split to 31 A. R. Battersby D. G. Buckley E. McDonald and D. C. Williams J.C.S. Chem. Comm. 1977 115. 32 A. R. Battersby D. G. Buckley G. L. Hodgson R. E. Markwell and E. McDonald in ‘High Pressure Liquid Chromatography in Clinical Chemistry’ ed. P. F. Dixon C. H. Gray C. K. Lim and M. S. Stoll Academic Press London 1976 pp.63-70. 33 Ref. 2 p. 825. 34 A. R. Battersby D. W. Johnson E. McDonald and D. C. Williams J.C.S. Chem. Comm. 1977 117. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis NH HN /p m H,N-/ A NH HN /’ H,NJ (16d) 13Cat 0 (1 part) + (16) Unlabelled (3 parts) deaminase-cosynthetase [plus unlabelled (3)] Scheme 8 unsplit signals from C-15 was in agreement with an intramolecular rearrangement of ring D exactly as had been found earlier for PBG These results show clearly that deaminase-cosynthetase does catalyse the formation of uro’gen-I11 (3) when AP.AP (16) is provided and further that the enzymic conversion involves an intramolecular rearrangement. Nevertheless they do not prove that free AP.AP (16) is a biosynthetic precursor which is normally dimerized by the enzymes.Eventually it became clearz6 that two molecules of AP.AP (16) might be reacting chemically to produce the unrearranged tetrapyrrole system (26) which as it is formed could be transformed enzymically into uro’gen- 111 as in Scheme 9 (see below). At this stage it is appropriate to consider the results of other workers. In their work with pyrromethanes the Frydman~’~~~~ employed enzymes from wheatgerm and used paper chromatography to separate the isomeric porphyrins prior to radioassay. They found that AP.AP (16) in the presence of PBG was converted (ca. 1%) into uro’gen-I (8) by deaminase alone but they did not observe incorporation of AP.AP (16) into uro’gen-I11 (3) with deaminase-cosynthetase when they used a short incubation (1h).In the light of the results quoted pre- viously it seems probable that the decisive differences between the experiments of the groups at Cambridge and Buenos Aires were the duration of the incubation and 35 B. Frydman S. Reil A. Valasinas R. B. Frydman and H. Rapoport J. Amer. Chem. Soc.,1971 93 2738; R. B. Frydman A. Valasinas and B. Frydman Biochemistry 1973,12,80; R. B. Frydman A. Valasinas H. Rapoport and B. Frydman F.E.B.S. Letters 1972,25 309. 404 D. G. Buckley the concentration of pyrromethane. When the rearranged [‘4C]PA.AP[labelled (18)J was incubated with deaminase-cosynthetase together with PBG radioac- tivity (ca. 0.7%) appeared in the uro’gen-111 (3). Later incubated the ‘headless’ pyrromethane (24) with PBG and deaminase-cosynthetase and found that there was 0.15-0.89% yield of radioac- tivity in the type-I11 porphyrins.Both sets of results were thought to prove that the (24) 14Cat * synthesis of type-I11 porphyrin is controlled at the pyrromethane level. However the evidence given above (and some of what follows) is so overwhelming that this cannot be correct The small transfers of radioactivity from rearranged pyr- romethanes into uro’gen-I11 (3) could reasonably be explained as arising from various well-known minor chemical ~ide-reactions.~~ The amounts of radioactivity found in the type-111 porphyrins in both of these studies with rearranged pyr- romethanes are of the same order ( < 1YO)as were found by the Cambridge groupz3 for the three rearranged aminomethylpyrromethanes (17)’ (18) and (19).Furthermore none of the foregoing weakly radioactive type-111 porphyrins from experiments with rearranged pyrromethanes has been degraded so as to locate the labels.* Proof that Rearrangement Occurs at the Tetrapyrrole Level.-Groups at Stutt- ga~t~~ and Cambridge37 have reported the involvement of the bilane (26) in .~~ uro’gen-I11 biosynthesis. Muller et ~1prepared the bilane (26) and reported that it was transformed into a uro’gen mixture having a type-I type-111 ratio of 84 16 by deaminase-cosynthetase from P. sherrnanii. From a different synthesis Battersby and McDonald et al.37prepared the crystalline lactam ester (25) which was hydrolysed to the same bilane (26) corresponding to unrearranged head-to- tail joining of four PBG units.This cyclked chemically (without enzyme) at pH 7.2 to give virtually pure (>95%) uro’gen-I (8) isolated as uroporphyrin-I and analysed by h.p.1.c. as the coproporphyrin isomer as described previou~ly.~~ However incubation of the bilane (26) with purified deaminase-cosynthetase gave a markedly different result the products after aromatization were uroporphyrin-I11 (70%) derived from (3) and uroporphyrin-I (30%) derived from (8). The differences in the isomer ratios from the two experiments were probably due to the different concentrations of purified enzymes but both sets of results strongly suggested that the unrearranged bilane (26) is a key precursor in the biosynthesis of uro’gen-I11 (3).The Cambridge group have now established beyond doubt that this is the case.26 *The Reporter has attempted to set out clearly the relevant work in this area but must declare his interest in having been involved in the Cambridge effort. 36 H.-0. Dauner G. Gunzer I. Heger and G. Muller 2.physiof. Chem. 1976,357 147. 37 A. R. Battersby E. McDonald D. C. Williams and H. K. W. Wurziger J.C.S. Chem. Comm. 1977 113. Biological Chemistry-Part (iii) Tetrapyrroles and their Biosynthesis [ 15-13C]Bilane (26a)37 was converted into a product consisting of 80% uro’gen-111(3a) and 20% uro’gen-I (8a) by the deaminase-cosynthetase system as shown by h.p.1.c. analysis of the derived coproporphyrin esters. The crystalline copro- porphyrin-I11 ester was shown by I3C n.m.r.to be labelled specifically at C-15 by comparison with the spectrum of unambiguously synthesized [ 15-13C]copropor-phyrin-I11 tetramethyl ester. This established specific incorporation of the bilane (26a) into uro’gen-I11 (3a). The two [13C,]bilanes (26b) and (26c) were prepared3* in such a way that the enrichment was 90 atom% at each labelled site and so 81% of the molecules of each bilane sample were doubly labelled as illustrated in Scheme 9. After dilution with unlabelled bilane the two mixtures were incubated separately with purified deaminase-cosynthetase. The locations of labels in the resultant samples of uro’gen-I11 (3b) and (3c) were shown to be as illustrated in Scheme 9 by the usual isolation decarboxylation and 13C n.m.r.analysis; [20-13C]coproporphyrin-III tetramethyl ester was synthesized to allow 0 Me0,C (25) Unlabelled (26) %labelled (25a) 13C at C-15 (26a) C at C-15 (25b) lltC at (26b) lltC at 0 (2%) Cat A (26c) Cat A enzymic J 1 (8) lJ$abelled (3) Unlabelled (8a) C at one bridge (3a) 13C at C-15 (8b) ::Cat0 (3b) 13Cat. (8c) Cat A (3c) 13cat A Scheme 9 ’’ A. R.Battersby C. J. R. Fookes,E. McDonald and M. J. Meegan J.C.S. Chem. Comm. 1978 185. 406 D. G. Buckley the assignment of C-20 to be confirmed.26 Most importantly both I3C n.m.r. spectra showed a 72Hz doublet for the major resonance from the labelled bridge carbon atom;38 the two 13Catoms in each case have therefore become directly bonded as illustrated for (3b) and (3c) via an intermolecular reaction.The foregoing combined results prove that intact incorporation of unrearranged bilane (26) into uro’gen-III(3) occurs with inversion of ring D by an intramolecular process exactly as was found for PBG. Thus it is now certain that the biosynthesis of the natural type-I11 porphyrins chlorins and corrins involves the following steps. Four PBG units are joined together head-to-tail and the resultant bilane bound covalently or by physical forces to the enzyme system is then converted into uro’gen-I11 (3)by an intramolecular rearrangement which directly affects only ring D and the two carbon atoms which become C-15 and C-20.266 Battersby and McDonald have suggested26 that in the absence of cosynthetase deaminase catalyses the cyclization of the bilane to join C-20 and C-19 to give uro’gen-I (8) as shown in Scheme 6 but that in the presence of cosynthetase the combined enzyme system causes cyclization between C-20 and C- 16 rather than C-20 and C-19 (Scheme 10).This postulated attack would produce the spiro- intermediate (27); the labelling arising from (25b) and (2%) is shown. Frag-mentation of the C-15-C-16 bond followed by cyclization as shown would generate uro’gen-I11 (3) (Scheme 10). The spiro-system (27) is related to that proposed by Mathewson and C~rwin~~ in 1961 and its intermediacy is consistent with all the evidence available. Uro’gen-I11 (3) Scheme 10 4 The Pathway from Uro’gen-I11 to Protoporphyrin-IX Extensive studies’ over the past 25 years had indicated that the enzymic decar- boxylation of the four acetic acid side-chains of uro’gen-I11 (3)to give copro’gen- I11 (4) is a stepwise process and intermediates with seven six and five carboxy- groups had been detected in several laboratories.However it seemed that a single enzyme (or a highly organized enzyme complex) is able to effect the four successive decarboxylations although it must have a rather low substrate specificity. 39 J. H. Mathewson and A. H. Convin J. Amer. Chem. Soc. 1961,83 135. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis Pure heptacarboxylic acid porphyrins have been isolated from various sources including haemolysed avian erythrocyte^,^**^' the urine of patients with por- ~hyria,~~ and rat It now seems very probable that these porphyrins are identical and they have been variously named phyriaporphyrin porphyrin-208 and pseudouroporphyrin.From a series of spectroscopic analyses and by synthesis of three of the four possible isomers Battersby and McDonald showed that the heptacarboxylic acid porphyrin isolated from chicken erythrocytes had the struc- ture (28);40this assignment was confirmed subsequently by using the pyrromethene method.43 The heptacarboxylic acid porphyrin isolated from the faeces of rats poisoned with hexachlorobenzene was shown by Jackson et to have the same structure (28) by synthesis in this case using the b-oxobilane This work was part of the Cardiff group’s investigation of the porphyrins excreted during both normal and abnormal metaboli~m,~~ details of which are given in the following two sections.(28) Phyriaporphyrin-III Intermediates between Uro’gen-111 and Copro’gen-111.-Four heptacarboxylic six hexacarboxylic and four pentacarboxylic acid porphyrins might be formed by successive decarboxylations of the acetic acid side-chains during the conversion of uro’gen-III(3) into copro’gen-I11 (4) and a major aim of the Cardiff group was to discover whether or not there was a specific (or preferred) route and whether this was the same in both normal and abnormal metab01ism.~~ After extensive pre- liminary work on isolation procedures and analytical techniques it was possible to carry out preparative-scale separations of the porphyrins excreted in the faeces of rats that had been poisoned with hexachlorobenzene.Ip this way 10-20 mg of each of the octa- hepta- hexa- and penta-carboxylic fractions were obtained all of which were shown to be type-I11 porphyrins by decarboxylation to coproporphyrin- 111. The octacarboxylic acid was readily shown to be uroporphyrin-111; the other fractions were essentially homogeneous and their structures were then deduced and confirmed by synthesis. The heptacarboxylic acid had the structure (28) (see above) which is now generally termed phyriap~rphyrin-III.~’-~~ Of the six possible isomeric hexacar- 40 A. R. Battersby E. Hunt M. Ihara E. McDonald J. B. Paine 111 F. Satoh and J. Saunders J.C.S. Chem. Comm. 1974,994. 41 A. R. Battersby E. Hunt E. McDonald J.B. Paine 111 and J. Saunders J.C.S.Perkin I 1976 1008. 42 A. H. Jackson H. A. Sancovich A. M. Ferramola N.Evans D. E. Games S. A. Math G. H. Elder and S. G. Smith in ref. 4 pp. 191-206. 43 R. L. N. Harris A. W. Johnson and I. T. Kay J. Chem. SOC.(C) 1966,22. 44 cf. A. H. Jackson and K. M. Smith in ‘The Total Synthesis of Natural Products’ ed. J. Apsimon Wiley London and New York 1974 p. 144. 408 D. G. Buckley boxylic acid porphyrins which can be derived from uro’gen-I11 (3) only structure (29) was comEatible with the findings of a detailed spectroscopic analysis. This assignment was confirmed4* by synthesis of the hexamethyl ester by the MacDon- ald and by comparison with the ester derived from the natural compound. The pentacarboxylic acid was deduced to have the structure (30) by a combination of spectroscopic and biosynthetic arguments; other porphyrins derivable from structure (30) had been identified earlier.45 Synthesis of the pentamethyl ester of (30) and comparison with the ester of the natural compound confirmed this assignment .(29) R=A (30) R=Me Most of the possible isomeric penta- hexa- and hepta-carboxylic acid porphy- rins have been synthesized in Cardiff,42 and some have been synthesized indepen- dently by other groups.41y46 Biosynthetic studies with the porphyrinogens derived from the isomeric penta- hexa- and hepta-carboxylic acid p~rphyrins~~ showed that the porphyrinogens corresponding to the isolated porphyrins (28) (29) and (30)were metabolized at least as fast as those from the synthetic isomers.The fact that each of the isolated porphyrins was homogeneous strongly suggests that the parent porphyrinogens did not arise by a diversion from the normal metabolic pathway; the low specificity of the enzyme suggests that this would be most unlikely. All these combined with the that the heptacarboxylic acid porphyrins from haemolysed chicken erythrocytes and from humans with porphyria are the same as that from rat faeces strongly suggest that the porphyrinogens (31) (32) and (33) are the major intermediates in both the normal and abnormal metabolic conversion of uro’gen-I11 (3) into copro’gen-I11 (4). The major effect of hexachlorobenzene which is well known to induce porphyria in animals and humans,47 seems to be simply to slow down the overall rate of decarboxylation by reducing the activity of the enzyme.Thus the biosynthesis of copro’gen-I11 (4) from uro’gen-III(3) does involve a series of discrete steps as predicted by previous inve~tigators,~*~~ and the preferred (and possibly specific) pathway is shown in Scheme 11. One striking feature of the preferred pathway [(3) +(31) +(32) +(33) +(4)] is that decarboxylation occurs in a clockwise fashion starting with the acetic acid side-chain on ring D of uro’gen-I11 (3) and proceeding by successive decarboxyl- 4s M. S. Stoll G. H. Elder D. E. Games P. O’Hanlon D. S. Millington and A. H. Jackson Biochem. J. 1973,131,429. 46 P. S. Clezy T. T. Hai and P. C. Gupta Austral. J. Chem.1976,29 393. 47 Reviewed briefly in ref. 42. 409 Biological Chemistry -Part (iii) Tetrapyrroles arzd their Biosynthesis ..flP NH HN (4) Copro’gen-111 (33) Scheme 11 ations of the acetic acid residues on rings A B and C to form copro’gen-111 (4) (Scheme 11). It has been suggested that the uro’gen-III (3) in effect ‘performs a cartwheel’ on the enzyme surface as the side-chains are de~arboxylated.~~ However this intriguing suggestion is largely speculative and as yet the nature of the enzyme (or group of enzymes) involved is undefined. In contrast to the above result~,~*~~* which show that decarboxylation of the acetic acid side-chains of uro’gen-I11 (3) starts with ring D and finishes with ring c during its converion into copro’gen-I11 (4) only the acetic acid group on ring c of uro’gen-I11 (3) is decarboxylated during the formation of the corrin nucleus of vitamin BIZ,cf.(2). Thus the pathway to the corrins diverges from that to the chlorins and natural porphyrins immediately after the formation of uro’gen-I11 (3).48 Akhtar’s have defined the stereochemistry of the decarboxylation of the acetate side-chains of the cand D rings of uro’gen-111. (2R)-[2-2Hl,2-3H1]Succinic acid (34)49was incubated with a haemolysed chicken erythrocyte preparation and was incorporated into the acetate residues of uro’gen-III(35) (Scheme 12); this on decarboxylation generated chiral methyl groups in copro’gen-I11 (36) and then in haemin (37). The labelled haemin (37) was degraded’ to ethyl methyl maleimide and haematinic acid (38) which are derived from rings A and B and rings C and D respectively.Ozonolysis of (38)gave labelled acetic acid (39)’ which was converted 48 For recent reviews see (a)ref. 26a and (b) A. I. Scott Accounts Chem. Res. 1978,11,29. 49 G. F. Barnard and M. Akhtar J.CS. Chem. Comm. 1975,494. 410 D. G. Buckley (35) Uro'gen-I11 (36) Copro'gen-I11 (partial) 1 HT R = CT=CDT PI=CDTCDTC02H Scheme 12 into labelled malic acid (40).50a Incubation of (40) with fumarase and analysis of the results using the method5' of Cornforth and Arigoni showed that the labelled acetic acid (39) had the (S) configuration as illustrated in Scheme 12. Thus the decarboxylation reaction converting the uro'gen-III(3) into copro'gen-III(4) must have occurred as in (35)+(36) (Scheme 12) i.e.with retention of configuration. It is highly likely that this result holds good for decarboxylation of all four acetic acid side-chains although the above result only refers to acetic acid residues of rings c and D. Akhtar that the mechanism of the decarboxylation reaction involves enzymic protonation of an intermediate such as (35b) formed by enzyme-catalysed decarboxylation of the enzymically protonated porphyrinogen (35a) (Scheme 13). 5" (a)A. I. Rose J. Biof.Chem. 1970,245,6052; (b)J. W. Cornforth J. W. Redmond H. Eggerer W. Buckel and C. Gutschow Nature 1969,221 1212; J. Luthy J. Ritey and D. Arigoni ibid. p. 1213. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis 41 1 Biosynthesis of Protoporphyrin-IXfrom Copro’gen-111.-As was noted earlier the enzymes involved in the transformation of uro’gen-I11 (3) into protoporphyrin-IX (6) are not highly specific,’ and thus results from the testing of putative precursors must be interpreted carefully.Initial had suggested that hardero’gen-111 (4 1) was a natural intermediate between copro’gen-I11 (4) and proto’gen-IX (5) although (41) was incorporated only 6-10 times more efficiently than its isomer (42) using an enzyme preparation from E. grucilis and the absolute incorporations were low. A recent investigation by the Cardiff group has established5’ that hardero’gen-I11 (41) is indeed an intermediate on the pathway to proto’gen-IX (5).The isomeric porphyrins (43) and (44)were prepared labelled with tritium in the meso-positions and were reduced with sodium amalgam to the corresponding porphyrinogens (41) and (42). The latter were incubated separately with haemolysates of mature chicken erythrocytes and after work-up [which included dilution with unlabelled (6)] the isolated protoporphyrin-IX dimethyl ester was purified by h.p.1.c. The specific incorporations of (41) and (42)were found to be 34 and 0.8% respectively but after allowing for the stereospecificity of the later enzyme-mediated aroma- tization reaction (5)-+(6),53 it is clear that the absolute incorporations of hardero’gen-I11 (41) and its isomer (42) must have been ca. 70 and 1.5% respec-tively. Mea;e Me I \ P P (4) R’=R~=P (5) R’= R2= CH=CH2 (41) R’= CH=CH2 R2= P (42) R’= P R2 = CH=CH2 (6) R’=R2= CH=CH;! (43) R’= CH=CH2 R2 = P (44) R’ = P R2= CH=CH2 Further support for the intermediacy of (41) came from a kinetic study of the conversion of (4) into (5).In either the same avian system or in experiments with rat liver homogenates (using h.p.1.c. analysis of the porphyrin esters obtained on work-up) only hardero’gen-I11 (41) was formed as an intermediate and none of the isomer (42) could be detected. Thus the normal biosynthetic route to proto’gen-IX (5) involves formation of the vinyl side-chain on ring A before modification of the propionic acid residue on ring B. Oxidative Decarboxylation of the Propionic Acid Side-chains. Early work in Cambridge and Southampton showed’ that when the propionic acid residues on ’’ J.A. S. Cavaliero G. W. Kenner and K. M. Smith J.C.S. Chem. Comm. 1973 183; J.C.S. Perkin I 1974,1188. D. E. Games A. H. Jackson J. R. Jackson R. V. Belcher and S. G. Smith J.C.S. Chern. Comm. 1976 187. ’’ (a)A. H. Jackson D. E. Games P. Couch J. R. Jackson R. V. Belcher and S. G. Smith Enzyme 1974 17 81 88; (6) R. Poulson and W. J. Polglase J. Biol. Chem. 1975 250 1269; (c) A. R. Battersby E. McDonald J. R. Redfern J. Staunton and R. H. Wightman J.C.S. Perkin I 1976 266. 412 D. G. Buckley both rings A and B of copro'gen-I11 (4) were oxidatively decarboxylated to give proto'gen-IX (9,only the pro-S-hydrogen atom from the methylene group adjacent to the macrocycle was removed and that each of the two vinyl groups was derived from the remaining three hydrogen and two carbon atoms without rear- rangement.The original work by Akhtar54 which had defined the stereospecificity of hydro-gen removal was based on incubation studies with labelled succinic acid. Recent work by the Cambridge group which has confirmed the previous findings was based on incubation of PBG stereospecifically labelled at C-8. This latter approach circumvented the difficulties encountered in the earlier work due to the incorpora- tion of label into each of the eight side-chains of protoporphyrin-IX (6). (8S)-[8-3Hl]PBG (44)was synthesized26" as shown in Scheme 14. The initial hydrogenation step was accomplished using the new chiral homogenous catalyst (44) Scheme 14 developed by Knowle~;~~ the stereoselectivity was determined to be as shown by using model compounds and ca.92% of the derived amido-ester had the (2s) configuration. The labelled PBG (44) was mixed with ''C-labelled material to give a 3H:14C ratio of 8.7 1. This sample was converted enzymically into pro- toporphyrin-IX (6a) which had a 3H:14C ratio of almost one half of that of the PBG. Further degradation as illustrated in Scheme 15 (after hydrogenation of the vinyl groups) clearly showed that tritium had largely been lost during biosynthesis of the vinyl groups. The values found corresponded closely to those expected (shown in brackets) for ca. 92% configurational purity. This shows that it is the pro-8s-hydrogen atom of PBG which is removed during the formation of the vinyl groups of protoporphyrin-IX (6).Experiments using PBG specifically deuteriated in the propionic acid side-chain allowed the Cambridge group to determine the overall stereochemistry of the " Z. Zaman M. M. Abboud andM. Akhtar J.C.S. Chem. Comm. 1972 1263. 55 W. S. Knowles M. J. Sabacky B. D. Vineyard and D. J. Weinkauff J. Amer. Chem. SOC.,1975 97 2567. Biological Chemistry-Part (iii) Tetrapyrroles and their Biosynthesis .CO,H enzymic 3H I4C = 8.7 C02H CO,H (6a) 3H:I4C= 4.7 (4.7) H H A+B C+D 3H:14C= 0.64 H :I4C= 8.7 (0.7) (8.7) Scheme 15 oxidative decarb~xylation.~~ The required labelled PBG was prepared by reduc- tion of the dideuterio-acrylic ester (45) with di-imide which by its syn-stereo- specificity fixes the relative configuration at centres X and Y.This arrangement was not affected by the subsequent reactions which produced the racemate (46) + (47). An analysis of the possible outcome of overall anti- or syn-elimination (irrespec- tive of the precise mechanism) from the molecules (46) and (47) is given in Scheme 16; note that it is the pro-S-hydrogen atom which is lost from position X. By using a 'H n.m.r. analysis of the hydrogen atom at centre x in the derived proto- porphyrin-IX [structures (48)-(5 l)] neither product (SO)nor (5 1) from enan- tiomer (47) will register and a clear 'H-'H coupling pattern should be observed from products (48) or (49). Under suitable conditions separate signals could be seen from H on each of the vinyl groups of the protoporphyrin-IX dimethyl ester.So this ester derived enzymically from the labelled PBG [(46) and (47)] was examined by 'H n.m.r. in this way and two doublets with trans-coupling (18 Hz) were observed from the two H [see (48)]. Thus both vinyl groups of pro- toporphyrin-IX (6) are formed by an overall anti-elimination and the absolute stereochemistry of this process is as shown in Scheme 17. Also illustrated there is the important reaction which generates the vinyl group of isopentenyl pyrophos- hate;^' the correspondence is striking.26" Of all the mechanisms which have been proposed for formation of the vinyl groups of proto'gen-IX (5),only the two given in Scheme 18 are compatible with A. R. Battersby E. McDonald H.K. W. Wurziger and (in part) K. J. James J.C.S. Chem. Cumm. 1975,493. 57 J. W.Cornforth R. H. Cornforth G.Popjak and L. Yengoyan J. Bid. Chem. 1966 241 3970. 414 D. G. Buckley CO,CH,Ph HD "'y C0,CH2Ph + PhCH20eD N\ N H H \I DH (45) ,$+,C02CH2 Ph /% D"H JH H$ x' D (48) (49) Haem, PorphyrinHc + %HD Porphyrin < -+ chlorophyll and H~ cytochromes CO H Hc ?H HI)-Steroids and terpenoids Hc Scheme 17 the above data.* These represent possible mechanisms for the two known types of enzymes one of which requires oxygen while the other operates in anaerobic conditions. For this latter enzyme mechanisms involving hydride abstraction have * Variations of the mechanisms given in Scheme 18 are possible (see ref.5 pp. 102-104) but those given represent the two main types. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis been proposed but there is no experimental evidence in .this area. It has been suggested that the oxygen-requiring enzyme coproporphyrinogenase acts by first hydroxylating the propionic acid side-chain and then by catalysing the elimination of carbon dioxide and water; antiperiplanar elimination would require retention of configuration in the hydroxylation step (Schemes 17 and 18). Hydride acceptor H Then ring B Proto’gen-IX (as ring A) (5 ) Jwvwwy (4) Copro’gen-111 (41) Hardero’gen-I11 (partial) Tenrymic (4) H CO,H Porphyrin Porph yrin (52a) (52b) (53) ‘Porphyrin S-411’ Scheme 18 Incubation studies with derivatives of copro’gen-111 (4) hydroxylated in the side-chain of either ring A or ring B were inconclu~ive.~ However indirect evi- dence for the involvement of the ring-A-hydroxylated porphyrinogen [as (52)J has been presented by both and Cle~y.~~ They independently deduced the structure of ‘porphyrin S-411’ from meconium to be (53) and Jackson suggested that this probably arises by the more favoured chemical elimination of water [from (52b)l rather than carbon dioxide and water [from (52a)l.A consideration of the Newman projections (52a) and (52b) indicates strong steric interaction between the porphyrin ring and the carboxy-group in (52a) which is absent in the conformation (52b) required for anti-elimination of water to give the trans-acrylic acid side-chain of (53).It thus seems that the normal metabolic process requires enzymic assis- tance to hold the side-chain in the correct conformation for fragmentation to the ’* P. W.Couch D. E. Games and A. H. Jackson J.C.S. Perkin I 1976,2492. s9 I. A. Chaudhry P. S. Clezy and V. Diakiw Austral. J. Chem. 1977,30,879. 416 D. G.Buckley vinyl group whereas the formation of porphyrin S-411in meconium may be due to non-enzymic loss of water. Alternatively porphyrin S-411may be an artefact produced on work-up from the hydroxypropionate porphyrin (52). In either case the involvement of the hydroxylated derivative (52) is likely.58 Arornatization of Proto'gen-IX (5). Although the autoxidation of porphyrinogens occurs readily in daylight to give the corresponding porphyrins clear evidence has been obtained for enzymic aromatization of proto'gen-IX (5) in oiz~o.~~ The prod- uct protoporphyrin-IX (6),is the last intermediate common to the biosyntheses of both the haems and the chlorophylls.As a result of the work described above its biosynthesis has now been defined and it is of considerable interest that the same pathway is followed in organisms as diverse as bacteria higher plants birds and mammals. 5 The Iron and Magnesium Branches The Haemoproteins.-An enzyme ferrochelatase is known to catalyse the chela- tion of Fe2+ by protoporphyrin-IX (6) to give protohaem (54). Protohaem (54) itself is the prosthetic group of haemoglobin myoglobin and the cytochromes-b.Protohaem is also the precursor of the cytochromes-c in which the protein is covalently bound to the haem by the addition of an -SH residue to each vinyl side-chain. The cytochromes-a have as their prosthetic group a considerably modified protohaem carrying a long hydrocarbon side-chain and they have been shown to be derived from protohaem (54)in Staphylococ~us.~ The structure of porphyrin C derived from the cytochrome-c of yeast and of horse heart has been shown to be 3,8-di(ar-S-cysteinylethyl)deuteroporphyrin-IX (55) by a series of degradative synthetic and n.m.r. studies.60 A recent synthesis of haemin C (56)has been achieved61 from haemin (20) as shown in Scheme 19. The CO,H I CO,H H-C-NHZ I I H-C-NH, I (20) Haemin (55) + X t= H H Porphyrin C (56) X =Fe"'-Cl Haemin C + Reagents i Cysteine n-C16H33NMe3 Br- room temp.02,NaBH4 pH 8.1 Scheme 19 J. T. Slama H. W. Smith G. C. Willson and H. Rapoport J. Amer. Chem. Soc. 1975,97 6556. 61 S. Kojo and S. Sano J.C.S. Chem. Comm. 1977 249. Biological Chemistry-Part (iii) Tetrapyrroles and their Biosynthesis iron atom of haemin was found to play an important role in the synthesis but other observations suggested that the reactive intermediate was not a simple Fe"-pro- toporphyrin [as (54)j. Cytochrome-c oxidase is a key respiratory enzyme and its prosthetic group(s) have attracted many studies since Warburg's isolation62 of the first crude metallo- porphyrin preparation called haem A. A block to further progress in this area had been the difficulty of demonstrating homogeneity for haem A preparations or more importantly of isolating the corresponding metal-free porphyrin(s) A.New work by groups in Australia and Cambridge has that the 'porphyrin A' dimethyl ester from beef heart (whether under acidic or basic condi- tions) was a mixture of two similar compounds in roughly equal amounts. Investi- gation of the more polar compound has not been reported but the crystalline less polar ester (designated porphyrin A dimethyl ester) has been shown to have the structure (57).63 This confirms that the structure of haem A is (58) as was suggested earlier.64 The of porphyrin A dimethyl ester (57)was part of Clezy's investigation of biologically significant porphyrins much of which has been reported re~ently.~~ HO <CO,H <CO,H <CO,R CO R< (54) Protohaern (57) R=Me +X+ =H,H (58) R = H,X = Fe" Haem A The ChlorophyUs.-Research on the late stages of the biosynthesis of chlorophylls has been hindered by the insolubility of intermediates and relevant enzymes.The pathway first outlined by Granick66 in 1951 has been generally supported by the numerous investigations since then,5 and recent work by Jones67 has confirmed that the steps between protoporphyrin-IX (6) and chlorophyllide-a (63)in higher plants are as given in Scheme 20. The enzyme which catalyses the conversion of chlorophyllide-a (63) into chlorophyll-a (64) has not been characterized. However chlorophyllase the 62 0. Warburg and H.-S.Gewitz Z. physiof. Chern. 1951,288 1. M. Thompson,J. Barrett E. McDonald A. R. Battersby C. J. R. Fookes I. A. Chaudhry P. S. Clezy 63 and H. R. Morris J.CS. Chem. Comm. 1977 278. 64 See ref. 63 and ref% 2-4 cited therein. 65 See P. S. Clezy and V. Diakiw Austral. J. Chem. 1975,28 2703; P. S. Clezy and C. J. R. Fookes ibid. 1977.30 1799; and refs. therein. 66 S. Granick Ann. Rev. Pfunr Physiol 1951,2 115. 67 0.T. G. Jones,in ref. 4 pp. 207-225. 418 D. G.Buckley Protoporphyrin-IX + Mg Protoporphyrin-IX + (6) (59) CO,H CO,Me (60) 1 (61) R=C=CHZ 1 (63) R = H Chlorophyllide-a (62)R = CH2CH3 Protochloroph yllide- a (64) R.= phytyl Chlorophyll-a (65) Chlorophyll4 (66) Bacteriochlorophyll-a Scheme 20 Biologica1 Chemistry-Pa rt (iii ) Te trap yrroles and their Biosy nthesis 419 enzyme which catalyses the reverse (hydrolysis) reaction of chlorophyll-u (64) to give (63) and phytol (67) may also catalyse the biosynthetic esterification which generates chlorophyll-a (64); this would probably occur in a lipid environment within the cell.’ An alternative e~planation~~ may be that phytol (67) is not the natural substrate for the synthetic reaction catalysed by chlorophyllase and that late stages in phytol (67) biosynthesis occur after some other C, alcohol [e.g.all- trans-geranylgeraniol (69)68] has been esterified. Although the biosynthesis of the chlorophyll macrocycle has been studied exten- si~ely,~,~~,~~ much less was known about the pathway to phytol(67) until recently.” Reasons for this lack of information included difficulties in both obtaining pure phytol (67) and devising specific degradations of the labelled alcohol (67) obtained from feeding experiment~.~~ Battersby et aL70 have now defined conditions for the isolation of pure phytol (67) from cells of Euglena grucilis.The method involves separation of the phytol carbamate (68) from the corresponding derivative of geranylgeraniol which gives both C, alcohols as their correspondiog crystalline biphenyl-4-ylcarbamates (68) and (70). This allowed them to study the incorporation of [l-I3C]acetate into (67) R=H Phytol (68) R=CONH (69) R = H Geranylgeraniol (70) R=CONH phytol (67) and their results are summarized in Scheme 21.The labelling pattern found supports the operation of the normal terpenoid pathway to geranylgeranyl pyrophosp hate7* with subsequent reduction. These results do not distinguish between initial formation of the geranylgeranyl ester of protochlorophyllide-a (62) or chlorophyllide-a (63) followed by reduction or prior reduction of (69) to phytol (67) before esterification.68 However the methods developed should facilitate further studies of this pr~blem.~’ The Bacteriochlorophylls.-Unlike the higher plants in which only chlorophylls-a (64) and -b (65) are normally found the green photosynthetic bacteria use a wide ‘* J. J. Katz H. H. Strain A. L. Harkness M.H. Studier W. A. Svec T. R. Janson and B. T. Cope J. Amer. Chem.SOC.,1972 94 7938; C. Liljenberg Physiol Plant. 1974 32. 208 and refs. cited there. ‘’ G. W. Kenner J. Rimmer K. M. Smith and J. F. Unsworth in ref. 4 pp. 255-276. ’O E. H. Ahrens jun. D. C. Williams and A. R. Battersby J.C.S. Perkin I 1977 2540. 71 See ref. 70 and refs. 7-9 cited therein. 72 G. Popjak and J. W. Cornforth Biochem. J. 1966 101 553 and refs.cited therein; G.P. Moss in ‘Terpenoids and Steroids’ ed. K. H. Overton (Specialist Periodical Reports) The Chemical Society London 1971 Vol. 1 p. 221 and refs. cited therein. 420 D. G. Buckley :? / * RO (64) R =chlorophyllide-a residue .=13c Scheme 21 range of different chlorophylls for their energy-gathering activities. These bacteriochlorophylls differ in the substituents around the periphery of the macro- cycle and although it appears that bacteriochlorophyll-a (65) arises by modification of chlorophyllide-a (63) in Rhodopseudomonas spheroides,’ recent work has shown that (63) is not an intermediate in the biosynthesis of other bacteriochloroph y Kenner ef al.69have studied the structures of the various Chlorobium chloro- phylls (650) and (660) from certain Chloropseudomonas species; the designations (650)and (660) refer to the wavelength (in nm) of the red electronic absorption band.Distribution between hydrochloric acid and ether on Celite columns separates both the (650)and (660) chlorophylls into six components (or ‘bands’) in each case. The structures of the six components of the (650) chlorophylls had been determined beyond (see Table 2) and although the structures of the (660) series were less certain,69 bands 5 and 6 of the chlorophylls (660) had been shown to be as in Table 2.Many of the differences between the Chlorobium chlorophylls and chlorophylls-a and -b involve simple modifications around the periphery of the macrocycle which are common to all of the former group. There has been considerable confusion as to the substituent on the S-meso- carbon (C-20) in bands 1-4 of the (660) series. It is now clear that all of the chlorophylls (660) carry a methyl substituent at C-20,69but the structures given in Table 2 for bands 1-4 of the (660) series are less certain. Kenner ef al. have suggested these structures on the basis of a series of synthetic degradative and biosynthetic studies.Their for the biosynthesis of the (660) chloro-phylls are outlined in Scheme 22. They suggest that the pentacarboxylic acid porphyrinogen (33) is the branch from normal chlorophyll metabolism (Scheme 20) for bands 2 4 and 5 of chlorophylls (660); this suggestion was made before it was known4* that (33) is a normal intermediate in porphyrin biosynthesis (see above). 73 J. L. Archibald D. M. Walker K. B. Shaw A. Markovac and S. F. MacDonald Canad.J. Chem. 1966,44 345; R. A. Chapman M. W. Roomi T. C. Morton D. T. Krajcarski and S. F. MacDonald ibid. 1971 49 3544. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis 421 Table 2 Structures of the Chlorobium chlorophylls R2 R3 (650) series R'= H (660) series R'= Me P Bu' Prn R2.R3 Et Et band 1 2 R2 Pr"(Bu')? Bu' R3 Me Et Bu' Et Me Et 3 4 Bu'(Pr")? Pr" Me Et Pr" Me 5 Et Et Et Me 6 Et Me The carboxylic acid groups on the substituents at C-8 and C-12 would activate the side-chain for methylation by S-adenosylmethionine. This could occur first on the substituent at C-12 to give (71) after decarboxylation of the C-12 residue which would lead to (660) band 5. Alternatively methylation of (72) on the propionic acid side-chain at C-8 either once or twice would lead to (660) band 4 or (660) band 2 respectively. Scheme 22 also shows the favoured for the formation of chlorophylls (660) bands 1 3 and 6; it was this proposal that led to the structures given for bands 1 and 3 in Table 2.Methylation of (73) once or twice would give after decarboxylation either n-propyl or isobutyl substituents at C-8 whereas simple decarboxylation of (73) would lead to the 8-ethyl substituent known73 for chloro- phyll (660) band 6. Kenner et al. have also pointed out that the (650) chlorophylls which differ from the (660) series in that meso-methylation does not occur contain fractions which have 8-n-propyl- 12-methyl (band 5) and 8-isobutyl- 12-methyl (band 3) substituent arrays; rneso-methylation of these would lead to the structures proposed for chlorophylls (660) bands 1 and 3. Another bacteriochlorophyll has been isolated from both Chlorobium phaeobac- teroides and C. phaeouibrioides and has been designated bacteriochlorophyll-e.74 This was shown to be a mixture of the three structures shown in (74).These are clearly related to the Chlorobium chlorophylls (660),69 the only significant difference being the formyl group at C-7 in (74) and now the Chlorobium chloro- phylls (650) and (660) are termed bacteriochlorophylls-d and -c respe~tively.~~'~~ It H.Brockmann jun. in ref. 4 pp. 277-285. 422 D. G.Buckley P Me -Uro'gen-111 (3) PP (33) Copro'gen-111 (4) I P Me V Me Me Me Me PP (71) (73) V Me band 6 band I?A.band 3? P P (72) V =CH=CH2 Scheme 22 H HO..kMe (74) R =Et Pr" or Bu' Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis is of interest that the various bacteriochlorophylls-c -d and -e all have the (R)-configuration at the hydroxyethyl side-chain at C-3.74,75 6 The Biosynthesisof Vitamin B, Coenzyme B, (75) is the biologically active form of vitamin B, (76) and this complex molecule presents formidable challenges to chemists.Determination of the and the total of the vitamin are among the great achievements in organic chemistry. The elucidation of the biosynthesis of vitamin BIZand the determination of its role and mechanism of action in biology78 are two further challenges which are under active inve~tigation.~’~~ Me HO OH (75)Coenzyme B12 (76)Vitamin BIZ X=CN 2 2 HO The origin of the complex side-chain attached at C-17 has been but this Report will be concerned only with the biosynthesis of cobyrinic acid (Z) the natural corrin nucleus. In common with the porphyrin nucleus this consists of four pyrrole rings built into a macrocycle with the important difference of a direct C-1 to C-19 link in the corrins.Furthermore the acetate and propionate side-chains of ’’ H. Brockmann jun. and N. Risch Angew. Chem. In&rnaf.Edn. 1974,13,664. ’‘ D. C. Hodgkin J. Pickworth J. H. Robertson K. N. Trueblood R. J. Prosen and J. G. White Nature 1955,176,325; R. Bonnett J. R. Cannon A. W. Johnson I. Sutherland A. R. Todd and E. L. Smith ibid. 1955 176 328. 77 (a) R. B. Woodward Pure Appf. Chem. 1973 33 145; (b) A. Eschenmoser XXIIIrd IUPAC Congress Boston Pure Appl. Chem. Suppl. 1971,2,69; (c)A. Eschenmoser Naturwiss. 1974,61,513; (d)A. Pfaltz B. Hardegger P. M. Muller. S. Farook B. Krautler. and A. Eschenmoser Helu.Chim. Acta 1975 58. 1444. T. C. Stadtmin Science 1971,171,859. 79 P. Renz and R. Weyhenmeyer F.E.B.S. Letters 1972 22 124; S. H. Lu and W. L. Alworth Biochemistry 1972 11,608 and refs. cited therein. 424 D. G. Buckley cobyrinic acid (2) are clearly arranged as in the natural type-I11 porphyrins with the characteristic ‘inversion’ in ring D. By late 1974 the existence of a shared biosynthetic pathway to porphyrins and corrins had been demonstrated by the incorporation of 13C-and l4C-labe1led ALA and PBG into cobyrinic acid.5 It was also known that methionine acted as the source of seven of the eight methyl groups of cobyrinic acid (2) including that at C-1; the eighth the pro-12s-methyl group was known to arise by decarboxylation of the C-12 acetic acid ~ide-chain.~.~~”~’ However even after several sets of experiments in various laboratories it was not certain that uro’gen-I11 (3) was an intermediate in the biosynthesis of cobyrinic acid (2).5,48 Proof that vitamin BI2(76) is derived from uro’gen-III(3) has now been obtained from various experiments with bacterial whole-cell and cell-free preparations81 carried out in several laboratories (see Scheme 23).48,82-84 Scott showed that CO,H enzymes ___* < < CO,H CO,H CO,R C02R (2) R =H unlabelled (3) Unlabelled (77) R =Me unlabelled = l3C (77g) m = l3C (3g) = I4C (3h) 0 = 14C (77h) R=Me Scheme 23 incubation82 of the doubly labelled uro’gen-I11 (3f) (3H :14C=4.10 1) in the cell-free system from Propionibacterium shermanii gave after dilution with carrier and purification of the recovered heptamethyl cobyrinate (77) (‘cobester’) a radio- chemically pure sample of cobester (77f) (3H 14C=4.05 1).Any randomization via fragmentation and recombination would have led to a profound change in the 3H 14C specific activity ratio of this unsymmetrically substituted substrate. Further evidence was obtained on administrations2 of [5 15-’3C2]uro’gen-III (3g) to resting A. I. Scott in ref. 4 pp. 303-318. ” A. I. Scott B. Yagen and E. Lee J. Amer. Chem. SOC.,1973 95 5761; A. R. Battersby European Symposium in Bio-organic Chemistry Gregynog Wales May 1973; see also ref. 836. ’* A. I. Scott B. Yagen N. Georgopapadakou K. S. Ho S. Klioze E. Lee S. L. Lee G. H. Temme 111 C.A. Townsend and I. M. Armitage J. Amer. Chem. SOC.,1975,97,2548; 1976,98,2371. (r3 (a)A. R. Battersby M. Ihara E. McDonald F. Satoh and D. C. Williams J.C.S. Chem. Cornm. 1975 436; (b)A. R. Battersby E. McDonald R. Hollenstein M. Ihara F. Satoh and D. C. Williams J.C.S. Perkin I 1977 166. 84 H.-0. Dauner and G. Miiller 2.physiol. Chem. 1975 356 1353. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis 425 whole cells of P. shermanii. In this case pure vitamin B12(76) was recovered; this was shown to be labelled in the corrin nucleus as illustrated in (77g) by a 13C n.m.r. analysis (4.5 YOspecific incorporation). The Cambridge group used the specifically labelled uro’gen-I11 (3h)83 in their studies which demonstrated S-8% specific incorporations of (3h) into cobester (77h) using a similar cell-free preparation.” Dauner and Muller have reporteds4 high incorporations of a mixture of uro’gens-I (8) -11 -111 (3) and -1V (labelled equivalently in each pyrrole ring) using a cell-free system from Clostridium tetunomorphum.They have also achieved similar incorporations with Battersby’s [12-methylene-14C]uro’gen-III (3h),83b using the same cell-free preparation from C. tetanomorphum. These results firmly establish that uro’gen-I11 (3) is a specific biosynthetic precursor of cobyrinic acid (2) and thus of vitamin BI2(76) itself. By inspection the biosynthetic conversion of uro’gen-I11 (3) into cobyrinic acid (2) requires the following structural changes (a) introduction of seven methyl groups from methionine at C-1 C-2 C-5 C-7 C-12 (pro-R),C-15 and C-17; (b) decarboxylation of the acetic acid side-chain at C-12; (c) extrusion of C-20; (d) possible adjustments of the oxidation level; and (e) insertion of cobalt.Scott suggested8’ that the first step could be decarboxylation to give the ring-c- methyl heptacarboxylic acid porphyrinogen (78) and subsequently reporteds2 a 0.1% incorporation of the 14C-labelled form (78a) into cobester (77) of unknown labelling pattern using the cell-free system from P. shermanig1 This result was interpreteds2 as confirmation that uro’gen-I11 (3) suffers decarboxylation (at C-12) prior to the necessary reductive methylation steps. Independent work by the Cambridge groups3 also demonstrated that incubation of the 14C-labelled porphyr- inogen (78b) leads to labelled cobester (77) after the usual work-up.However they concluded that the ring-c-methyl porphyrinogen (78) was probably not a normal intermediate in corrin biosynthesis. They reached this conclusion mainly because the porphyrinogen (78) was 30-50 times less effective as a precursor of cobyrinic acid (2)than was uro’gen-I11 (3) while the ring-c-methyl porphyrinogen (78) and uro’gen-I11 (3) were almost equally well incorporated into copro’gen-I11 (4) in the same cell-free The incorporations of l4C-labe1led (78) were so low in both that the recovered cobester (77) could not be degraded to locate the site(s) of labelling. Groups in Zurichs6 and Cambridge83b*87 have shown that each of the seven methyl groups in cobyrinic acid (2) derived from methionine is incorporated intact into the corrin nucleus.The Yale groups8 independently determined that the methyl groups at C-12 (pro-R)and C-1 of vitamin B12 (76) are incorporated intact. Intact incorporation had been demonstrated previously by the Cambridge group for the methyl groups at C-12 (pro-R)and C-7,89 but the most important result concerned the methyl group at C- 1. 85 A. I. Scott E. Lee and C. A. Townsend Bioorg. Chem. 1974 3 229; A. I. Scott Tetrahedron 1975 31 2639. a6 M. Imfeld C. A. Townsend and D. Arigoni J.C.S. Chem. Comm. 1976,541. 87 A. R. Battersby R. Hollenstein E. McDonald and D. C. Williams J.C.S. Chern. Comm. 1976 543; see also ref. 836. 88 A. I. Scott M.Kajiwara T. Takahashi I. M. Armitage P. Demou and D. Petrocire J.C.S. Chem. Comm. 1976,544. 89 A. R. Battersby M. Ihara E. McDonald J. R. Stephenson and B. T. Golding J.C.S. Chem. Comm. 1973,404; 1974 458; J.C.S. Perkin I 1977 158. 426 D. G.Buckley P Me Me P A-@+M;;R Me p (78) Unlabelled (79) (78a) rn = 14C (79a) R=H =14C (79b) R =CH20H (78b) The question of loss or retention of the methyl hydrogen atoms is of particular importance in the case of this 1-methyl group of vitamin B12 (76) as it bears critically on current theories concerning the mechanism of formation of the cor- rinoid C-1-C-19 bond.” Each of the groups used essentially the same methods in their recent studies they incubated [Me-13CD3]methionine (90 atom ‘/o 13C 98 atom YO D) with intact cells of P.shermanii and examined the recovered vitamin B, (76) by 13C n.m.r. spectroscopy. The Cambridge and Zurich groups used deuterium-noise-decoupled 13C Fourier-transform n.m.r. spectroscopy which showed that each of the seven methionine-derived methyl groups including that at C-1 had been incorporated without exchange of D with H of the medium; none of the signals of the 13C-enriched carbon atoms displayed the large splitting (Jca. 125 Hz) expected for 13C-’H spin-spin coupling. The Yale group reached the same conclusion about the incorporation of the 1-methyl group using a different n.m.r. method. These results rule out the intermediacy of any system in which the potential 1-methyl group is temporarily a methylidene residue,” e.g.(80) although the existence of an intermediate seco-corrin such as (79) would be compatible with the above results. In principle C-20 could be lost’ from the system at any oxidation level between methanol and carbon dioxide and this could occur at various stages in the forma- tion of the corrin ring e.g. before bond formation between C-l and C-19 OCCU~S,~’ or as a consequence of it. Recent work by indicates that C-20 is lost as formaldehyde possibly from a species such as (79b); electrocyclic ring closure of the product (79a)90 would lead to a dehydrocorrin which may then be reduced by insertion of Co’+ rather than CO~+.~” However there are many other possibilities and further experimental work is required. Sirohydrochlorin.-The prosthetic group of the widespread class of enzymes which catalyse the six-electron reduction of sulphite to sulphide was first characterized in 1973 by Kamen and Siegel’l and was named sirohaem.Removal of the iron afforded an orange fluorescent compound sirohydrochlorin (8l) which was shown to be an isobacteriochlorin. It was suggested9’ that sirohydrochlorin might arise by two C-methylations at C-12 and C-18 of uro’gen-III(3) and it was also noted that 90 A. Eschenmoser Chem. SOC.Rev. 1976,5 377; see also refs. 26a 486 77d,and 85. 9’ L. M. Siegel M. J. Murphy and H. Kamen J. Biol. Chem. 1973,248 251. 92 M. J. Murphy L. M. Siegel H. Kamen and D. Rosenthal J. Biol. Chem. 1973,248 2801. Biological Chemistry -Part (iii) Tetrapyrroles and their Bios yn thesis 427 sirohydrochlorin could represent an early intermediate in the biosynthesis of vitamin B12(76).92 In 1976 Bykhovsky’s group in Moscow the isolation of a methylated tetrapyrrole which contained cobalt from P.shermanii. The metal-free form of this compound appeared to be similar to sirohydrochlorin incorporated radioactive methionine into its methyl groups and furthermore increased the rate of vitamin B12 production in the organism. Muller’s group in Stuttgart then reportedg4 the isolation of ‘Factor 11’ from P.shermanii and showed that labelled forms of ‘Factor 11’ were incorporated into cobyrinic acid (2) by an enzyme preparation of C. tetanomorphum. The Cambridge and Moscow groups working in collaboration sho~ed~’,~~ that the isobacteriochlorin from P.shermanii was the same as the sirohydrochlorin obtained from the sulphite-reducing organism Desulphovibrio gigus. Finally ‘Factor 11’ was shown26u to be identical with sirohydrochlorin. Chemical and spectroscopic work by’the Cambridge and Moscow groups led to the postulation of two alternative structures for sirohydrochlorin; the A-B structure (81) and an isomeric B-c structure although the former was Recent work by the Cambridge group has rigorously established the structure (81) for sirohydrochlorin and its specific incorporation into cobyrinic acid (2) has also been dem~nstrated.~~ The origin of the two C-methyl groups of sirohydrochlorin was confirmedY7 by incorporation of (2S)-[Me-’3C]methionine,using D. gigas and examination of the product @la) by 13Cn.m.r.spectroscopy. Incubation of (2S)-[Me-’4C]methionine with P. shermanii under suitable conditions gave labelled sirohydrochlorin (81b). The purified ester (82) was proved to be radiochemically pure and the derived labelled acid (81b) was then incubated in the broken cell from P. sher-manii; the incorporation into cobyrinic acid (2b) isolated as cobester (77b) was in the range 3-7’/0. Ozonolysis of the purified cobester (77b) gave the fragments (83) (84) and (85),98the radioactivities of which confirmed that the labelling pattern was shown in Scheme 24 (* = 14C). These results when combined with those noted above e~tablish~~-~~ that siro- hydrochlorin has the structure and absolute configuration (81) and that sirohaem is the corresponding iron complex.The proven97 efficient enzymic conversion of sirohydrochlorinI-(81) into cobyrinic acid (2) confirms the Cambridge group’s earlier findings36 that the heptacarboxylic acid (78) is not the next intermediate beyond uro’gen-I11 (3) en route to vitamin B, (76) contrary to what had been thought.” The middle section of the biosynthetic pathway to vitamin B, can now be defined as uro’gen-I11 (3)-+ (81)-+ (2) -+ vitamin BI2(76). ?They envisage that the biosynthetic intermediate may be a dihydro-derivative of (81) which would be the product expected from simple methylation in rings A and B of uro’gen-I11 (3) (see refs. 26a and 486). 931 V. Ya. Bykhovsky N. I. Zaitseva A. V. Umrikhina and A. N. Yavorskaya Priklad. Biokhim. Mikrobiol.1976,12 825 and refs cited therein. 94 R. Deeg H.-P. Kriemler K.-H. Bergmann and G. Miiller 2.physiol. Chem. 1977,358 339. 95 A. R. Battersby E. McDonald H. R. Morris M. Thompson D. C. Williams V. Ya. Bykhovsky N. I. Zaitseva and V. N. Bukin Tetrahedron Letters 1977 2217. 96 A. R. Battersby K. Jones E. McDonald J. A. Robinson and H. R. Morris Tetrahedron Letters 1977 2213. 97 A. R. Battersby. E. McDonald M. Thompson and V. Ya. Bykhovsky J.C.S. Chem. Comm. 1978 150. 98 D. Arigoni E.T.H. Zurich; personal communication to A. R. Battersby quoted in ref. 97. 428 D. G. Buckley Uro’gen-111 enzymic he’ \ CO R CO R (82) R =Me * = 14C (8 1) R =H Unlabelled @la) R =H * = 13C (81b) R =H * = 14C lenrymic C0,Me I 2 Me 0 < C0,Me CO R t.0:R (84) (2b12 R =H * = l4G (77b) R =Me * = 14C Scheme 24 In his recent review,48b Scott describes the work of the Yale group with siro- hydrochlorin which confirms both the structure as (81) and the intermediacy of sirohydrochlorin* in the biosynthesis of vitamin BIZ.Interestingly they found that (81) and its dihydro-derivative were both efficiently incorporated into cobyrinic acid (2).7 Miscellaneous New Techniques.-The extensive survey of laboratory methods made available early in 1975 by Fuhrhop and Smith in the book edited by K. M. Smith2 has now Of been published ~eparately.~~ the three most important new techniques * He also envisages that the intermediate may be a dihydro-derivative of (81); see footnote on p.427. as J.-H. Fuhrhop and K. M. Smith ‘Laboratory Methods in Porphyrin and Metalloporphyrin Research’ Elsevier Amsterdam 1975. Biological Chemistry -Part (iii) Tetrapyrroles and their Biosynthesis developed since the early 1970s only the use of 13C-labelling was sufficiently well advanced to be included in detail in ref. 2.5The crucial role played by '3C-labelling and the associated I3C n.m.r. techniques in the elucidation of various parts of the biosynthesis of porphyrins chlorins and corrins has been published subsequently and is described abo~e.~~,~~~*~~ The Cambridge' 1*12*23*41 and Cardiff42745 groups have used 'H and 13C n.m.r. spectroscopy of porphyrin esters in the presence of various amounts of shift reagents"' to show the distribution of the side-chains which flank the four meso positions.This technique has both facilitated the identification of various natural porphyrin~~~,~~ and the confirmation of their structure by comparisons of the esters of the natural and synthetic compounds. The use of shift reagents and of other new techniques which change n.m.r. spectra as probes for the study of chlorophyll chemistry has been reviewed in a recent Meldola Medal Lecture."' Other important new work in the area of chlorophyll chemistry using the n.m.r. method has been reported by Katz et al."' High-performance liquid chromatography (h.p.1.c.)"' has been used very suc-cessfully by various groups in the past four years for the efficient separation of different porphyrin type^''^ and more importantly for the otherwise very difficult separation of isomeric p~rphyrins.~ 1*32,5'v5' The efficient separation of all four coproporphyrin isomer^,^^.^' which was not possible until re~enfly,''~ was one of the crucial developments by the Cambridge group in their successful work on the 'type-I11 pr~blem'.'~ Much of the recent work by the Cambridge and Cardiff groups has relied heavily on h.p.1.c.for both analytical and preparative separations of porphyrins (see above). Bile Pigments.-O'Carra has reviewed the biochemistry of haem cleavage and associated chemical analogues. lo5 Oxidative cleavage of protohaem (54) at the a-rneso-carbon (C-5) and loss of the iron atom normally gives biliverdin-IXa (86) although in isolated cases oxidative attack does occur at one of the other meso positions.In mammals the biliverdin-IXa (86) is immediately converted into bilirubin (87) (sometimes named bilirubin-IXa) by enzymic reduction (Scheme 25). The structures shown for biliverdin-IXa (86) and bilirubin (87) with the (2) configuration about each of the three or two exocyclic double bonds are what might reasonably be expected from their mode of formation; the particular tautomers shown have been accepted on the basis of various spectroscopic studies. O6 The first X-ray analysis of any naturally occurring linear tetrapyrrole has been reported recent1y.lo6 This study of bilirubin confirms that the structure is as shown in (87) thus confirming the gross chemical structure assigned to bilirubin by Fisher loo J.K. M. Sanders Chem. SOC.Rev. 1977,6 467. lo' H. Scheer and J. J. Katz in ref. 2 pp. 399-524; J. J. Katz W. Oettmeier and J. R. Norris in ref. 4 pp. 227-254; M. J. Wasielewski U. H. Smith B. T. Cope and J. J. Katz J. Arner. Chem. SOC.,1977,99 41 72. lo2 L. R. Snyder and J. J. Kirkland 'Introduction to Modern Liquid Chromatography' Wiley New York 1974. '03 Ref. 32 and accompanying papers. Ref. 2 pp. 859-861. lo' P. O'Carra in ref. 2 pp. 123-153. lo6 R. Bonnett J. E. Davies and M. B. Hursthouse Nature 1976 262 326. 430 D. G. Buckley Protohaem (54) O2+reductant knzymic 1 co+iron 2H CO H CO,H C0,H C0,H (86) Biliverdin-IXa (87) Bilirubin Scheme 25 et al.lo’ There is considerable intramolecular hydrogen bonding in the crystalline bilirubin (Figure 1); the low solubility of bilirubin in water which has important biological consequences can be understood readily in terms of this pattern of hydrogen bonding.lo6 Since bilirubin (87) is derived directly from biliverdin-IXa (86) and the former has the same configuration about the two exocyclic double bonds as is found in protohaem (54) it is clear that biliverdin-IXa (86) has the illustrated (2)configuration at the C-5 and C-15 double bonds. The stereo-chemistry of the C-10double bond of biliverdin-IXa has not been determined but presumably it also has the (2)configuration shown in (86). c-0 0 .. .. H ‘0-c Figure 1 Structure of bilirubin in simplified form. (Reproduced by permission from Nature 1976,262,326) lo’ H.Fischer H. Plieninger and 0.Weissbarth 2.physiol. Chem. 1941 268 231. Biological Chemistry-Part (iii) Tetrapyrroles and their Biosynthesis 43 1 Haemoglobin/Myoglobin Model Studies.-The respiratory haemoproteins haemoglobin and myoglobin transport and store molecular oxygen and thus are essential to the life of all vertebrates.”’ The most significant property of haemo-g10bin’~’ is co-operative oxygen binding the oxygen affinity of the biologically active tetramer increases with increasing saturation.lOg.llo Co-operativity is required for the transfer of oxygen from the carrier haemoglobin to the receptor myoglobin as well as for responses to other physiological requirements. The way that the protein in haemoglobin and myoglobin regulates oxygen affinity controls axial ligation of oxygen and provides kinetic stability to the iron-dioxygen group is under active investigation by the preparation and full characterization of synthetic model compounds.Since Collman’s synthesis of his ‘picket-fence’ porphyrin,’ which led to the isolation and characterization of a series of crystalline dioxygen-iron porphyrin complexes l1 many different groups have synthesized a wide variety of different iron porphyrins.’ l2 The different approaches used in these various studies have already helped to define the degree of hindrance required around the iron-dioxygen grouping to allow reversible oxygen binding,’ ” but further work is necessary before these model studies can make a significant contribution to our understanding of the chemistry of the binding of oxygen to haemoglobin and myoglobin in uivo.For recent reviews see N. W. Makinen in ‘Techniques and Topics in Bioinorganic Chemistry’ ed. C. A. McAuliffe Wiley New York,1975 Part 1 Chapter 2; J. H. Prat ibid. Part 2 Chapter 7. M. F. Perutz Brit. Med. Bull. 1976,32 193. ‘lo J. M. Baldwin Brit. Med. Bull. 1976 32 213. J. P. Collman R. R. Gagne T. R. Halbert T.-C. Marchon and C. A. Reed J. Arner. Chem. SOC.,1973 95,7868; J. P. Collman R. R. Gagne C. A. Reed T. R. Halbert G. Lang and W. T. Robinson ibid. 1975,97 1427. J. P. Collman Accounts Chem. Res. 1977 10 265.

ISSN:0069-3030    

DOI:10.1039/OC9777400392

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

14 Biological Chemistry Part (iv) Enzyme Chemistry By M. C. SUMMERS Department of Biochemistry University of Cambridge Tennis Court Road Cambridge CB2 IQW and 0.C. WILLIAMS Department of Biochemistry Trinity College Dublin 2 Ireland 1 Irreversible Enzyme Inhibitors Irreversible enzyme inhibitors constitute a specific type of affinity labelling in which the inhibitor because of its similar structure to the natural substrate binds to the enzyme and subsequently becomes covalently attached to it.’ One class of irreversible inhibitor is the substrate analogue which carries a reactive functional group and by virtue of its structural similarities to the natural substrate binds at the enzyme active site.* Accordingly the effectiveness of this class of inhibitor depends on the binding affinity of the inhibitor for its target enzyme and the availability of reactive amino-acid residues at the enzyme active site.Another class of irreversible enzyme inhibitor is the k,, inhibit~r,~ where the enzyme substrate(s) carries a masked chemically reactive group and only after enzymic transformation is a reactive molecule produced. The product depending on its reactivity and availability of a suitable nucleophile either dissociates from the enzyme or becomes covalently attached. Inhibitors of this class have also been euphemistically referred to as ‘Suicide inhibitor^'.^ Irreversible inhibitors can provide information on the amino-acid residue(s) involved in the inactivation and the peptide sequence of the region enclosing the position of inactivation.In addition inhibitors of this type may be used to deter- mine the reactive pK of an amino-acid group involved in the ina~tivation.~ ’ Methods in Enzymology Vol. XLVI. ‘Affinity Labelling’ ed. W. B. Jakoby and M.Wilchek Academic Press N.Y.and London 1977; E. Shaw in ‘The Enzymes’ ed. P. D. Boyer Academic Press N.Y. and London 3rd ed. 1970 vol. 1 Ch. 2. * (a) M. Akhtar and D. C. Wilton Ann. Reports (B) 1973,70,98; (b)M. Akhtar and D. C. Wilton Ann. Reports (B),1971,68 167. (a) R. R. Rando Science 1974 185 320; (b) R. R. Rando. Biochem. Pharmacol. 1975 24 1153; (c) R. R. Rando Accounts Chem. Res. 1975,8 281. R. H. Abeles and A. L. Maycock Accounts Chem. Res. 1976,9 313. ’ (a)D. E. Schmidt and F.H. Westheimer Biochemistry 1971 10 1249; (b) J. R. Knowles Crit. Rev. Biuchem. 1976,4 165; (c)K. Brocklehurst and H. B. F. Dixon Biochem. J. 1977,167,859. 432 433 Biological Chemistry-Part (iv) Enzyme Chemistry 2 Acetylenic Irreversible Enzyme Inhibitors The original discovery by Bloch et d6that acetylenic substrate analogues are effective irreversible inhibitors of their respective target enzymes has led to the synthesis and study of a large number of inhibitors of this type. In recent years acetylenic substrate analogues of diverse structure have been found to inhibit irreversibly As-3-keto-steroid isomerase (see later),’ flavin-linked oxidases,8 Cu2+- amine oxidases,’ y-cystathionase,” L-alanine aminotransferase,” thiolase,” and 4-aminobutyric acid aminotransferase (see below).Two of the flavin-linked oxidases which are inhibited by acetylenic substrate analogues have been investigated with regard to the structure of the flavin-inhibitor adduct viz. L-lactate oxidase (EC.1.13.12.4) and mitochondria1 monoamine oxi- dase (EC.1.4.3.4). L-Lactate oxidase from Mycobacterium smegrnatis catalyses the oxidative decar- boxylation of L-lactate to give acetic acid and C02.2“ Abeles and co-w~rkers~~ using 2-hydroxybut-3-ynoate (l) which is both a substrate and an irreversible inhibitor of the enzyme characterized the structure of the isolated flavin-inhibitor adduct as (2) and using a combination of spectroscopic and chemical methods presented evidence for the structure of the initially formed enzyme-bound flavin- inhibitor complex as (3) (Scheme 1).R R R I I I NH N 0 + H HCrC-C-CO2H I 0 R = -CH2-(CHOH)3-CH2-OPO3-H H a; chemical modification and isolation (1) Scheme 1 6 (a) G. M. Helmkamp R. R. Rando D. J. H. Brock and K. Bloch J. Biol. Chem. 1968,243,3229; (6) K. Bloch Accounts Chem. Res. 1969,2,193; (c)K. Endo and G. M. Helmkamp J. Biol. Chem. 1970 245,4293; (d)K. Bloch in ‘The Enzymes’ ed. P. D. Boyer Academic Press N.Y. and London 3rd ed. 1971 vol. 5 p. 441. 7 F. H. Batzold and C. H. Robinson J. Amer. Chem. SOC.,1975,97,2576. 8 (a) L. Hellerman and V. G. Erwin J. Biol. Chem. 1968,243,5234;(b)A. L. Maycock R. H. Abeles J. L. Salach and T. P. Singer Biochemistry 1976 15 114; (c) J.L. Kraus and J. J. Yaouanc Mol. Pharmacol. 1977,13,378; (d)J. L. Kraus J. J. Yaouanc and G. Stratz EuropeanJ.Med. Chem. 1975 5 507; (e) C. T. Walsh A. Schonbrunn 0.Lockridge V. Massey and R. H. Abeles J. Biol. Chem. 1972,247,6004 (f)T. H. Cromartie J. Fisher G. Koczorowski R. Laura P. Marcotte and C. T.Walsh Chem. Comm. 1974 597; (g) P. Marcotte and C. T. Walsh Biochemistry 1976 15 3070; (h) K. Horiike Y. Hishina Y. Migake and T. Yamano J. Biochem. (Japan) 1975,78,57; (i)T.H. Cromartie and C. T. Walsh Biochemistry 1975 14 3482. 9 (a) R. C. Hevey J. Babson A. L. Maycock and R. H. Abeles J. Amer. Chem. SOC.,1973,95,6125; (6) R. R. Rando and J. DeMairena Biochem. Pharmacol. 1974,23,463. 10 R. H. Abeles and C. T. Walsh J.Amer. Chem. SOC., 1973,95,6124. 11 P. Marcotte and C. T. Walsh Bioche-Biophys. Res. Comm. 1975,62 677. 12 P. C. Hollan M. G. Clark and D. P. $loxham Biochemistry 1973,12,3309. 13 A. Schonbrunn R. H. Abeles C. T. Walsh S. Ghisla H. Ogata and V. Massey Biochemistry 1976,15 1798. 434 M. C.Summers and D. C. Williams In the case of mitochondria1 monoamine-oxidase studies aimed at elucidating the structure of the flavin-inhibitor adduct have been undertaken using model ~ystems'~"~ and partially purified enzyme preparations.16 In both types of study when propargylamines e.g. 3-dimethylamino-prop-1-yne (4) are. used as inhibi- tors the same flavocyanine flavin-inhibitor adduct has been characterized. The characterized adduct (5) (Scheme 2) is the result of attachment of the C-1 atom of (4)to N-5 of the flavin nuc1eus.l' Several mechanisms were proposed by Abeles et al.to account for the structure of the flavocyanine (5) reaction between R R' ! R' I NH N 0 '0 + H/ C+CH Me / HC-C-CH2N \ Me Me (4) (5 ) R = -CH2-(CHOHh -CH2 -0-(P03-)2 -adenosine R = 8a-cysteinyl peptide Scheme 2 oxidized flavin and allenic carbanion; Michael addition of reduced flavin with oxidized substrate; and radical-pair formation of flavin and substrate with subsequent collapse and protonation.to give a stable covalent adduct. However a recent report by Krantz and Lipkowitz" indicates that the mechanism of inactiva-tion may be more complex than had previously been proposed.'6 These workers studied the irreversible inhibition of monoamine oxidase using the acetylenic inhibitor (6) and the allenic isomer (7) and observed distinct spectral properties for the respective flavin-inhibitor adducts with only the former inhibitor (6) giving a spectrum typical of a flavocyanine.Krantz and Lipkowitz18 argued that if one of Me /Me H / Me-C=C-CH2-N HZC=C=C-CH2-N \CH2Ph \CH2Ph (6) (71 l4 (a)B. Gartner and P. Hemmerich Angew. Chem. Internat. Edn. 1975,14 110; (6) A. L. Maycock J. Amer. Chem. Soc. 1975 97 2270. Is B. Gartner P. Hemmerich and E. A. Zeller European J. Biochem. 1976.63 211. 16 A. L. Maycock R. H. Abeles J. I. Salach and T. P. Singer Biochemistry 1976,15 114. 17 For recent reviews of the chemistry of flavins and flavoenzymes see (a)P.Hemmerich Fortschr. Chem. org. Naturstoffe 1976 33 451; (b)T. C. Bruice Prog. Bioorganic Chem. 1976 4 1; (c) 'Flavins and Flavoproteins' ed. T. P. Singer Elsevier Amsterdam 1976; P. Hemmerich V. Massey and H. Fenner F.E.B.S.Letters 1977,84,5. 18 A. Krantz and G. S. Lipkowitz J. Amer. Chem. SOC.,1977 99 4156. Biological Chemistry -Part (iu)Enzyme Chemistry 435 the three mechanisms proposed by Abeles et al. is correct then the mechanism of inactivation of inhibitors (6) and (7) should be very similar and give rise to the same flavin-inhibitor adduct. However this appears not to be the case. At the moment the structure of the flavin-allene inhibitor adduct is unknown. Apart from the use of acetylenic substrate analogues to inhibit flavin-linked enzymes they have also been used successfully irreversibly to inhibit pyridoxal phosphate-dependent enzymes.The mechanism of inactivation of a pyridoxal phosphate enzyme is illustrated by the work of Washtien and Abeles with 'y-cystathi~nase.'~ The enzyme is inhibited irreversibly by propargylglycine (8; 2-aminopent-4-ynoic acid); the inactivation displays pseudo-first order kinetics and is accompanied by the covalent attachment of inhibitor to the enzyme. In addition when radio-labelled (8) was used it was possible to isolate an inhibitor-enzyme adduct which on treatment with aqueous acid yielded (2S)-[2-'4C]-2-amino-4- ketopentanoic acid (9). The proposed mechanism of inactivation is shown in Scheme 3. From indirect evidence it was suggested that the active site nucleophile H H+ fl J HCrC-CH2-C-CO2H 4HYC-CHKCO,H + I NH2 HX (8) HN+ + PpI Py-CHO PY CH -CH-COY Py-CHO = Pyridoxal phosphate H3CK0 +AH3 Scheme 3 (9) (X) involved in covalent bond formation is either tyrosine or cysteine.Recently Washtien et d2*have shown that y-cystathionase catalyses exchange of the a-and l9 W. Washtien and R. H. Abeles Biochemistry 1977 16 2485. 2o W.Washtien A. J. L. Cooper and R. H. Abeles Biochemistry 1977,16,460. M. C. Summers and D. C. Williams &protons of (2S)-amino-acids that are unable to undergo y-elimination and yet are competitive inhibitors of the normal enzyme-catalysed reaction. The high specificity of k,, inhibitors makes them useful agents for the study of the in vim function of enzymes and in particular in the investigation of enzyme synthesis and degradation; e.g.Abeles and Walsh" found that when mice were injected i.p. with propargylglycine a condition similar to the genetic defect cysta- thionuria was induced. A particularly useful target enzyme in this respect is y-aminobutyrate-a-ketoglutarate transaminase [GABA-T (EC.2.6.1.19)l. The putative inhibitory neurotransmitter y-aminobutyric acid (10; GABA) is degraded via transamination with 2-oxoglutarate by pyridoxal phosphate- dependent GABA-T. Irreversible inhibitors of the enzyme include ethanolamine- O-sulphate,21 4-amino-hex-5-ynoic acid,22 4-amino-hex-5-enoic acid (1 1)23and the naturally occurring neurotoxin gabaculine (12; cyclohexa-l,3-dienyl-5-amino-carboxylic acid).24 The mechanism of inactivation of GABA-T by gabaculine involves Schiff base formation with pyridoxal phosphate tautomerization and finally aromatization to give m-carboxyphenyl pyridoxamine phosphate (1 3).Chemical studies by Rando and Bangerter25 support the mechanism outlined above and in particular that the structure of the inactivator adduct has the struc- ture shown and not the other possibility resulting from Michael addition at C-3. Interestingly the dihydro analogue (14) does not irreversibly inhibit the enzyme.25 DC02H /-fco2H (13) (14) Both (1 1) and (12) appear to be very specific k,, inhibitors of GABA-T. Thus i.p. injection of gabaculine solution leads to a dose-dependent loss of GABA-T activity and an increase in GABA levels in mouse brain.Other pyridoxal phosphate- dependent enzymes such as glutamate decarboxylase ornithine decarboxylase aspartate aminotransferase and alanine aminotransferase are not inhibited irre- ~ersibly.~~' Similarly 4-amino-hex-5-enoic acid (11) when administered peripherally causes both a dose-dependent irreversible inhibition of GABA-T and an increase of brain GABA in mice.26 The tlI2of GABA-T in mouse brain was *' L. J. Fowler and R. A. John Biochem. J. 1972,130 569. 22 M. J. Jung agd B. W. Metcalf Biochem. Biophys. Res. Comm. 1975,67 301. 23 B. Lippert B. W. Metcalf M. J. Jung and P. Cassara European J. Biochem. 1977,74,441. 24 (a) R. R. Rando and F. W. Bangerter J. Amer. Chem. SOC. 1976 98 6762; (6) K. Kobayashi S.Miyazawa and A. Endo F.E.B.S. Letters 1977 76 207; (c) R. R. Rando and F. W. Bangerter Biochem. Biophys. Res. Comm. 1977,76 1276. 25 R. R. Rando and F. W. Bangerter J. Amer. Chem. SOC.,1977,99,5141. 26 M. J. Jung B. Lippert B. W. Metcalf P. Bohlen and P. J. Schechter J. Neurochem. 1977 29 797. Biologica 1 Chemistry -Part (iv) Enzyme Chemistry 437 estimated to be 3.4 days. Also the inhibitor has little or no effect on L-glutamate decarboxylase (cf. 4-amino-hex-5-ynoic acid ref. 27) succinic semialdehyde dehydrogenase aspartate aminotransferase and alanine aminotransferase.26 3 Steroid Isomerases Rose,” in a review of aldose-ketose isomerases emphasized the importance of investigating the mechanism of action of enzymes catalysing a-hydroxyketone-a- hydroxyaldehyde interconversions which do not use sugar phosphates as substrates.Monder et a[.’’ have described an enzyme from hamster liver that catalyses the isomerization of the ketol side-chain of 11-deoxycorticosterone (DOC) to the corresponding hydroxy aldehyde (isoDOC). The proposed mechanism for the isomerization is shown in Scheme 4. Initial results obtained by Monder’s group indicate that the enzyme has both similar and different properties to the more extensively studied sugar phosphate i~omerases.’~*~~ The enzyme catalyses intramolecular proton transfer between C-21 and C-20 of the steroid side-chain; this is a common feature of other isomerases e.g. glucosamine-&phosphate iso- mera~e,~~ and triose phosphate is~merase.~~ glucose-6-phosphate i~omerase,~’ The generally accepted mechanism for intramolecular proton transfer to and from adjacent carbon atoms is that a single base (-B; Scheme 4)removes a proton 0 HB DOC OH HB-i isoDOC Scheme 4 from the substrate to give a cis-enediol intermediate and protonated enzyme (B-H) this is followed by protonation of the cis-enediol on the adjacent carbon 27 M.J. Jung B. Lippert B. W. Metcalf P. J. Schechter P. Bohlen and A. Sjoerdsma J. Neurochem. 1977 28 717. 28 I. A. Rose Adv. Enzymol. 1975 43,491. 29 (a) A. K. Willingham and C. Monder Endocrin. Res. Comm. 1974,l; 145; (b)C. Monder B. Zumoff H. L. Bradlow and L. Hellman. J. Clin. Endocrin. Metabolism 1975,40,86; (c)K. 0.Martin S.W. Oh H.J. Lee and C. Monder Biochemistry 1977,16,3803. 30 I. A. Rose Brookhaven Symp. Biol. 1962,15 293. 31 C. F. Midelfort and I. A. Rose Biochemistry 1977,16 1590 32 I. A. Rose and E. L. O’Connell J. Biol. Chem. 1961,236 3086. 33 J. M. Herliky S. G. Maister W. J. Albery and J. R. Knowles Biochemistry 1976 15 5601. 0- M. C. Summers and D. C. Williams atom. There appears to be a time-dependent stereoselective exchange of the C-21 protons. However Lee and M~nder~~ have evidence of a C-20 epimerase in their isomerase perparation and it is possible that the stereochemistry at C-20 deter-mines the stereochemistry of proton removal at C-21. Another isomerase which uses a steroid as substrate is A5-3-ketosteroid iso- merase and in this case the reaction catalysed is the isomerization of a A’-3- ketosteroid to the corresponding A4-3-ketosteroid e.g.(15) -+ (16) in Scheme 5. (15) R=O (17) R =H -CH(Me)-(CH2)3-CHMe2 Scheme 5 The enzyme from Pseudomonas testosteroni has been studied in detail and in fact was the first example found of an enzyme catalysing an intramolecular proton tran~fer.~’ However reinvestigationsf the mechanism of proton transfer for the P. testosteroni enzyme indicates that the proton transfer may not be as specific as had previously been assumed36 Vige? and Marquet have now shown that during enzyme-catalysed isomerization of A’-androstendione (15) there is not only 46 -D 6p hydrogen transfer but dso exchange of the 4p hydrogen. It appears therefore that the assumed dienol intermediate may be generated by removal of either the a or proton at C-4; at the moment there are no accurate data on the relative contribution of the various exchange processes in the overall mechanism i.e.46 +6p and 4a -D 6a proton migration; 4p and 4a proton exchange. It was mentioned earlier that P. testosteroni A’-3-ketosteroid isomerase is inhibited by 34 H. J. Lee and C. Monder Biochemistry 1977,16,3810. ’’ P.Talalay and V. S. Wang Biochim. Biophys. Acta 1955,18,300. 36 A. Viger and A. Marquet. Biochim. Biophys. Acta 1977,485,482. Biological Chemistry-Part (iu) Enzyme Chemistry acetylenic substrate analogues such as (19) in Scheme 6. In 1973 Martyr and Benisek3! reported that the enzyme is also inactivated irreversibly by light at wavelengths greater than 300 nm in the presence of A4-3-ketosteroids.It has now been shown that under the conditions of photoinactivation aspartic acid-38 in the polypeptide chain is decarboxylated to alanir~e.~* R &_ &L Inactivation (19) R=O (20) R = H -CH(M~)-(CHZ)~-CH(M~)~ Scheme 6 Cholesterol oxidase from Nocardia erythropolis has mechanistic similarities to the A5-3- ketosteroid isomerase described above. The enzyme oxidizes cholesterol (18) to cholest-4-en-3-one (16) via cholest-5-en-3-one (17) with hydrogen peroxide as the other product. Smith and Brooks using cholesterol stereospecifically deu- teriated at C-4 showed that the enzyme catalysed 4p +60 proton transfer and 4a-proton exchange.39 In addition the enzyme is inhibited irreversibly by the acetylenic substrate analogue (20).40 The mechanism of inactivation of the As-3-ketosteroid isomerase and cholesterol oxidase is most probably the same and involves proton loss from the a-carbon atom to give an allene (21) which reacts with an active-site nucleophile.This is outlined in Scheme 6. Whereas the bacterial AS-ketosteroid isomerase has been studied extensively the same cannot be said of the corresponding enzyme-catalyzed process of animal origin Benson and Talalay41 observed that human and rat liver cytoplasm contains As-ketosteroid isomerase activity which was stimulated specifically by reduced glutathione (GSH). They also noted that the molecular and physical properties of the partially purified isomerase were similar to a group of basic proteins isolated from rat (6 proteins designated AA A B C D and E) and human (5 proteins designated a,p 'y 6 and E) liver and referred to as glutathione-S-transfera~es.~~ The GSH-transferases catalyse the transfer of GSH to a wide range of small organic molecules such as epoxides and halobenzenes to give the corresponding thioether.Also it transpires that one of the GSH-transferases from rat liver is identical to ligandin (GSH-transferase B) an intracellular binding protein so termed because of its ability to 37 (a)R. J. Martyr and W. F. Benisek Biochemistry 1973,12 2172; (6)R. J. Martyr and W. F. Benisek J. Biol Chem. 1975 250. 1218. J. R. Ogez W. F. Tivol and W. F. Benisek J. Biol.Chem. 1977 252 6151. 39 A. G. Smith and C. J. W. Brooks Biochem. SOC.Trans. 1977 5 1088. 40 A. G. Smith and C. J. W. Brooks Biochem. J. 1977,167 121. 41 A. M. Benson and P. Talalay Biochem. Biophys. Res. Comm. 1976,69 1073. 42 W. B. Jakoby and J. H. Keen Trends Biochem. Sci. 1977,229. 440 M. C.Summers and D. C. Williams bind hydrophobic substrates such as bilirubin bromosulphophthalein drugs cortisol metabolites and azocar~inogens.~~.~~ Remarkably Benson et al.45have now shown that the same rat and human liver proteins are responsible for the GSH-activated As-3-ketosteroid isomerase activity. In rat liver the isomerase activity is associated mainly with ligandin (GSH-transferase B) while in humans all five GSH-transferases have isomerase activity but transferase y 6 and E are considerably more active than a and p.4 Biotin-requiring Enzymes Biotin acts as a CO carrier in a number of enzyme reactions where it functions either to accept (decarboxylases) to donate (carboxylases) or to transfer (trans- carboxylases) C0246,47 There are nine known biotin-requiring enzymes and the list includes transcarboxyla~e,~~ and acetyl-CoA carboxyla~e.~~ pyruvate carb~xylase,~~ The biotin is covalently linked to the &-amino group of a lysine residue to give a biotin carboxyl carrier protein (22) and this subunit transfers CO between two 0 A HN NH 0 (CH2)4-C-N-(CH2)4-lysyl peptide (22) active sites. Amino-acid sequence data of the biotin carboxyl carrier-protein of transcarboxylase acetyl-CoA carboxylase and several pyruvate carboxylases shows a high degree of conservation particularly around the biotin atta~hment-site.~~”~ However whether the amino-acid sequence serves as a recognition factor for the attachment of biotin to the apoenzyme or a conformational or catalytic role is not known.In general the reaction catalysed by a biotin enzyme is shown in Scheme 7. The overall reaction consists of two partial reactions first carboxylation of biotin by 43 (a) G. Litwack B. Ketterer and I. M. Arias Nature 1971 234 466; (b) G. J. Smith K. Huebrer and G. Litwack Biochem. Biophys. Res. Comm. 1977,76 1174; (c) A. Grahnen and I. Sjoholm European J. Biochem. 1977,80,573. 44 (a) A. J. Levi Z. Gatmaritan and I.M. Arias J. Clin. Invest. 1969 48 2156; (6) B. Ketterer P. Ross-Mansell and J. K. Whitehead Biochem. J. 1967 103,316; (c) K. S. Morey and G. Litwack Biochemistry 1969 8 4813. 4s A. M. Benson P. Talalay J. H. Keen and W. B. Jakoby Proc. Nut. Acad. Sci. U.S.A.,1977,74 158. 46 (a) H. G. Wood and R. E. Barden Ann. Rev. Biochem. 1977 46 385; (b) J. Kaappe Ann. Rev. Biochem. 1970,39 757. 41 J. Moss and M. D. Lane Adu. Enzymol. 1971,35,757. 48 (a) H. G. Wood and G. K. Zwolinski Crit. Reu. Biochem. 1976 4 47; (b) H. G. Wood in ‘The Enzymes’ ed. P. D. Boyer Academic Press N.Y. and London 3rd ed. 1972 vol6 p. 83. 49 (a) M. Scrutton and M. R. Yount in ‘The Enzymes’ ed. P. D. Boyer Academic press N.Y. and London 3rd ed. 1972 vol 6 p. 1; (6) M.F. Utter R. E. Barden and L. B. Taylor Ado. Enrymol. 1975,42 1. 50 (a)A. W. Alberts and P. R. Vagelos in ‘The Enzymes’ ed. P. D. Boyer Academic Press N.Y. and London 3rd ed. 1972 vol 6 p. 37; (b) M. D. Lane J. Moss and S. E. Palakis Current Topics Cell Regul. 1974,8 139. 51 (a)D. B. Rylatt D. B. Keech and J. C. Wallace Biochern.SOC.Trans. 1977,5 1544; (b)M. R. Sutton R. R. Fall A. M. Nervi A. W. Alberts P. R. Vagelos and R. A. Bradshaw J. Bid. Chem. 1977 252 3934. 441 Bio logica 1 Chemistry -Part (iu ) Enzyme Chemistry ATP +HC03-E-biotin xaccep tor-C02 X ADP +Pi E-biotin-COZ acceptor Scheme I HC03- and ATP and second transfer of CO to an acceptor to give carboxylated product. The decarboxylases carry out the second partial-reaction in reverse.The following discussion concerns recent studies on transcarboxylase (EC.2.1.3.1) which catalyses the transfer of C02 from methylmalonyl-CoA to biotin to give carboxybiotin. Consequently the enzyme does not require HC03-and ATP. The second partial-reaction is the carboxylation of pyruvate to oxaloacetate by carboxybiotin (Scheme 8). coz-c02-I x Me-C-COSCoA E-biotin &H2-:-CO2H H II Me-CH2COSCoA E-biotin-C02 Me-C-C02H II 0 Scheme 8 The enzyme is found in the propionic acid bacteria and it provides the mechanism by which propionate is formed in fermentation. Studies on the quater- nary structure of the 26s form of the enzyme have been published recently; the early studies being carried out on smaller more stable forms of the enzyme complex (18s form).The 26s form of transcarboxylase is composed of a central hexameric subunit of MW 360 000 (12s) and to this are attached two sets of three subunits on opposite sides of the central subunit. Each outside subunit is a dimer of MW 120 000 (5.8s) and each dimer is attached to the central subunit by two biotin carboxyl carrier proteins of MW 12 000 (1.3s). The 26s form of the enzyme is therefore made up of thirty individual proteins to give a complex of MW 1210 000. At acid pH the 26s form is stable but as the pH is raised selective dissociation occurs and as the pH is raised even higher only the central hexameric subunit remains intact.52 The methylmalonyl-CoA and pyruvate binding sites are on different subunits and as the enzyme displays two-site Ping-Pong kinetics the biotin ‘carries’ the CO from one binding site and delivers it to the The actual mechanism of C02 transfer from methylmalonyl-CoA to biotin and from biotin-C02 to pyruvate is not completely understood although a plethora of data has been obtained from kine ti^,'^ ~tereochernical,~~ subunit ~repla~ement,~~ ’* (a) H.G. Wood Fed. Proc. 1976 35 1899; (6) H. G. Wood J. P. Chiao and E. M. Poto J. Biol. Chem. 1977 252 1490; (c) N. G. Wrigley J. P. Chiao and H. G. Wood J. Biol. Chem. 1977 252 1500; (d)E. M. Pot0 and H. G. Wood Biochemistry 1977.16 1949. 53 (a) D. B. Northrop J. Biol. Chem. 1969 244 5808; (b) D. B. Northrop and H. G. Wood J. Biol. Chem. 1969,244,5820. 54 Y.F. Cheung C. H. Fung and C. T.Walsh Biochemistry 1975,14,2981. ” (a)H. G. Wood H. Lochmueiler C. Riepertinger and F. Lynen Biochem. Z. 1963,337,247; (6) M. Chueng F. Ahman B. Jacobson and H. G. Wood Biochemistry 1975.14 1611. 442 M. C. Summers and D. C. Williams isotope,56 and n.m.r. studies.” A plausible mechanism for CO transfer is shown in Scheme 9. The mechanism incorporates a pertinent observation by Rose et ul? who observed that transcarboxylase not only catalyses CO transfer between methylmalonyl-CoA and pyruvate but also proton transfer. When [3-3Hl]pyru- vate and unlabelled methylmalonyl-CoA were incubated together with trans-carboxylase a small amount of pyruvate-derived tritium was located in the pro-2R position of propionyl-CoA. Conversely incubation of (2R)-[2-3Hl]propiony1-CoA and unlabelled oxaloacetate resulted in the transfer of a small amount of tritium to pyruvate.Rose et al. considered biotin as the most likely proton transfer agent. Thus during transfer of CO to [3-3Hl]pyruvate via a cyclic mechanism as shown in Scheme 9 some tritium is transferred to the ureido oxygen of biotin which *H\ 0 NANH +X SCoA SCoA I / 0’/c ;c\ H* Me H + Scheme 9 is then converted to carboxybiotin by another molecule of methylmalonyl-CoA. The carboxylation of biotin by methylmalonyl-CoA must be sufficiently fast that complete exchange of the tritium with solvent does not occur and some of it ends up in propionyl-CoA. A modified mechanism to the one above has been proposed by Cleland.” However the problem of a concerted or stepwise mechanism for biotin-dependent carboxylation reactions is unresolved.60 5 Adenylate Cyclase Receptor Complexes Adenylate cyclase catalyses the conversion of adenosine-5’-triphosphateinto cyclic 3’,5’-adenosine monophosphate and plays an important role in the cellular modu- lation of regulatory signals.It is generally accepted that the extracellular messengers hormones bind to a receptor protein on the external surface of the cell membrane and this binding process activates the adenylate cyclase.61 Fundamental 56 I. A. Rose E. L. O’Connell and F. Solomon J. Biol. Chem. 1976 251,902. 57 H. G. Wood Trends Biochem. Sci. 1976,4. ”A. S. Mildvan Accounts Chem. Res. 1977,10,246. 59 W. W. Cleland Adv. Enzymol. 1977 45 273.6o J. Stubbe and R. H. Abeles J. Biol. Chem. 1977 252 8338. 6’ See M. F. Greaves Nature 1977 265,681. Biological Chemistry -Part (iu) Enzyme Chemistry 443 to the understanding of the mechanism of adenylate cyclase is the elucidation of the structural and functional organization of the receptor and cyclase molecules. Using the technique of radiation-enhanced inactivation using an electron beam the component sizes of the glucagon receptor-cyclase system from rat liver plasma membranes have been determined62 in the absence and presence of glucagon. The technique neatly demonstrated that in the absence of hormone the receptor and cyclase have molecular weights corresponding to their individual molecular weights and thus are probably unlinked.In the presence of glucagon associatian of receptor and cyclase takes place and the complex appears to be in the dimeric form with two molecules each of receptor and cyclase. The interaction between receptors and adenylate cyclase from different cells using the technique of cell fusion has also been The catecholamine receptor from turkey erythrocytes has been shown to activate and thus interact with adenylate cyclase from mouse erythroleukaemia cells within minutes of cell fusion. Recently it was dern~nstrated~~ that the catecholamine receptor can be donated and coupled to adenylate cyclase from a number of diverse cell types e.g. erythrocytes containing receptor have been fused with mouse adrenal tumour cells; rat glioma cells containing receptor have been fused with mouse erythroleukaemia cells.Thus evidence has been produced which supports the ‘mobile-receptor’ hypo- thesis that receptor and cyclase are freely dissociable in cell membranes. On agonist-receptor binding receptor-cyclase interaction is locked causing activation of cyclase and thus formation of CAMP to perform its regulatory functions within the cell. 6 Multienzyme Complexes Multi-enzyme complexes are aggregates of enzymes which catalyse two or more steps in a metabolic sequence the most-widely known example being fatty acid synthase a cluster of seven enzymes which catalyses the biosynthesis of fatty acids from acetyl- and malonyl-CoA. Many enzymes have been implicated in multi- enzyme complexes and the advantages of association of enzymes for metabolic pathways has been An extreme example of a multienzyme complex is a multifunctional polypeptide a single protein chain having more than one catalytic activity.Multifunctional polypeptides are common in the biosynthetic pathway to the aromatic amino-acids tyrosine phenylalanine and tryptophan; examples being; chorismate mutase-pre- phenate dehydrogenase of Escherichia tryptophan synthase of Neurospora cra~sa,~’ indol-3-yl glycerol phosphate synthase of E. coli,68 and 3-deoxy-~- arabino-heptulosonate 7-phosphate synthase-chorismate mutase of Bacillus 62 M. D. Housley J. C. Ellery G. A. Smith T. R. Hesketh J. M. Stein G. B. Warren and J. C. Metcalfe Biochim. Biophys. Acta 1977,467 208. 63 J. Orly and M. Schramm Proc.Nut. Acad. Sci. U.S.A.,1976,73 4410. 64 M. Schramm J. Orly S. Eimerl and M. Korner Nature 1977,268 310. See for instance L. J. Reed and D. J. Cox in ‘The Enzymes’ (Student Edition) ed. P. D. Boyer Academic Press New York 1970 vol. 1 Ch. 4. 66 B. E. Davidson E. H. Blackburn andT. A. A. Dopheide J. Biol. Chem. 1972,247,4441. 67 W. H. Matchett and J. A. DeMoss J. Biol. Chem. 1975 250,2941. “ T. E. Creighton and C. Yanofsky J. Bid. Chem. 1966 241,4616. 444 M. C.Summers and D. C. Williams s~btilis,~~ which all contain bi-functional polypeptides. A trifunctional polypeptide anthranilate synthase from N. crassa has also been de~cribed.~' The urom multienzyme complex of N. crassa has been shown'l to catalyse five consecutive steps in the aromatic amino-acid biosynthetic pathway the conversion of 3-deoxy-~-arabino-heptulosonate-7-phosphate (23) into 5-enoylpyruvoyl-shikimate-3-phosphate (28),the immediate precursor of chorismic acid which is itself the common precursor of tyrosine phenylalanine and tryptophan.The pathway proceeds via 3-dehydroquinate (24) 3-dehydroshikimate (25) D-shik- imate (26),and 3-phospho-shikimate (27) as shown in Scheme 10. CO,H HO CO,H CO2H HO 'O@OH* OQOH-OOOH C0,H CO,H POQOtCOZH CH OH OH -poooH (28) (27) P= Po3= Scheme 10 Recently a new procedure for the purification of the arom complex from N. crassa has been reported7* which minimized possible proteolytic damage to the enzyme. A homogeneous enzyme was obtained MW 270000 which under dis- sociating conditions produced apparently identical subunits of 165 000.Evidence was presented that proteolysis leads to progressive degradation of the complex into smaller subunits which retain enzymic activity thus accounting for the confusing subunit compositions previously obtained. It was concluded that the arom complex consists of two identical subunits each composed of a single polypeptide-chain capable of catalysing all five reactions. It would appear that discrete folding domains exist for each catalytic activity and that the domains have become connected as a result of fusion of the five structural genes coding for the enzymes and indeed it has been that the five genes occur as a cluster. The co-synthesis of these five activities thus provides an economy of synthesis of the enzymes of the biosynthetic pathway.69 L. Huang A. L. Montoya and E. W. Nester J. Biol. Chem. 1974,249,4473. '* F. M.Hulett and J. A. DeMoss J. Biol. Chem. 1975,250,6648. 71 N. H.Giles M. E. Case C. W. H. Partridge and S. I. Ahmed Proc. Nut. Acad. Sci. U.S.A.,1967,58 1453. '' J. Lumsden and J. R. Coggins Biochem. J. 1977,161,599. 73 S.R.Gross and A Fein Genetics 1960,45 885. 445 Biological Chemistry -Part (iu)Enzyme Chemistry Pyruvate dehydrogenase multienzyme complex74 from E. coli catalyses the reac- tion according to the generally accepted mechanism shown in Scheme 11. Pyruvate +NAD++CoA + Acetyl-CoA +NADH +H++C02 CoASH MeCOC02H r NADH Lip =Lipoic acid TPP =Thiamine pyrophosphate I NAD+ Scheme 11 The complex has a large molecular weight (-8 X lo6) and is composed of multiple copies of three different subunits having pyruvate decarboxylase (El) lipoate acetyltransferase (E2) and lipoamide dehydrogenase (E3) activity respec- tively.There has been some confusion as to the stoicheiometry of the subunits in the complex and the symmetry of the complex (see78). Evidence has been pr~vided~~.’~ for the involvement of a lipoyl-lysine ‘swinging arm’ which can transfer the ‘acyl’ moiety between subunits but the mechanism cannot be simple since each E2 subunit carries two functionally active lipoyl residues.77 Recent studies7’ on the self-assembly of the complex have demonstrated a 2 :1 stoicheiometry of El :E2and shown that the overall catalytic activity is proportional to the state of assembly of the complex.In the presence of [2-14C]pyruvate and absence of CoA the lipoic acid residues of the complex become acetylated and the reaction ceases. Thus a partial reaction involving El and E2 subunits can be studied while excluding that involving E3. It has been shown7’ that the depen- dance of acetylation of the E2 subunit on E1:E2 ratio (partially re-assembled complexes) is not as predicted by a simple El :E2 ratio of 2 :1 but rather by an El:EZratioof 24*2:1. Thus it would appear that each EZsubunit can be ‘catalytically serviced’ by 12 El dimers. On this basis a complex sub-structure is postulated consisting of a central E2 core a cube with octahedral symmetry comprising 24 polypeptide chains.Since each El dimer can acetylate half of the total E2 subunits and must perform this 74 L. J. Reed Accounts Chem. Res. 1974,7,40. 75 M. C. Ambrose and R. N. Perham Biochem. J. 1976,155,429. 76 H. J. Grande H. J. Van Telgen and C. Veeger European J. Bidchem. 1976,71 509. 77 M.J. Danson and R. N. Perham Biochem. J. 1976,159,677. 78 D. L.Bates M. J. Danson G. Hale E. A. Hooper and R. N. Perham Nature 1977,268 313 446 M C,Summers and D. C. Williams reaction indirectly (for direct acetylation large distances would have to be spanned) transacetylation reactions between E2subunits have been postulated. An El dimer bound to one of the E2subunits could cause direct acetylation of either 3 (or 4) E2 subunits. Indirect acetylation (transacetylation) could then occur between a directly-acetylated EZsubunit and either 3 (or 2) other Ez subunits.Thus only 12 EZsubunits could be serviced by each El dimer. This ‘transacetylation’ reaction provides a novel functional connection between active sites; however the significance of the reaction is not yet apparent.78 The possibility of interaction between the glycolytic enzymes and the advantages of such interactions have been frequently Recently direct evidence has been produced in favour of the presence of such glycolytic complexes. Glycolytic enzymes from rat skeletal muscle have been shown” to exist as a complex with myosin. However this situation could be regarded as an exclusive case being a consequence of accommodating rapid anaerobic respiration during muscle action.Recently a large aggregate has been isolated from E. coli spheroplastss1*s2which demonstrates all the enzyme activities of glycolysis. Gel chromatography demon- strated the presence of a fraction with high mol. wt. (1.6 X lo6) containing all the enzyme activities as well as low mol. wt. fractions (corresponding to the individual enzymes). Reassembly of the individual enzymes was demonstrated on concen- tration of the fractions. Total flux through the glycolytic pathway from [U-14 Clglucose to pyruvate was demonstrated. The presence of unlabelled glycolytic intermediates reduced the specific radioactivity of the pyruvate (isolated as alanine) by a much smaller extent than that expected for free mixing of intermediates and thus a functional organization within the complex is indicated.Another glycolytic complex has been reported83 from the parasitic protozoan Trypanosoma brucei where all the glycolytic enzymes are associated with a rapidly sedimentable particle on sucrose density gradient centrifugation. Latency studies have indicated that the enzymes were contained in a microbody which has been named the ‘glycosome’. These organisms when in the morphological form found in the host bloodstream rely completely on a modified glycolysis scheme for energy production the respiratory chain and citric-acid cycle enzymes being absent. Glucose is converted to pyruvate and NADH reoxidized via coupled glycerol-3- phosphate dehydrogenase :glycerol-3-phosphate oxidase. It would appear that the glycosome has developed to optimize conditions for glycolysis with high substrate and enzyme concentrations being maintained inside the microbody.79 See for instance C. de Duve in ‘Structure and Function of Oxidation-Reduction Enzymes’ ed..A. Akeson and A. Ehrenberg Pergarnon Press Oxford and N.Y. 1972 pp. 715-728. F. M. Clarke and C. J. Masters Biochim. Biophys.Acta 1973,327,233; 1974 358 193. J. Mowbray and V. Moses European J. Biochem. 1976,66 25. 82 D. M. Gorringe and V. Moses Biochem. SOC. Trans. 1978,6 167. 83 F. R. Opperdoes and P. Borst F.E.B.S. Letters 1977,80 360.

ISSN:0069-3030    

DOI:10.1039/OC9777400432

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

Author Index Aalbersberg W. G. L. 63 Aasen S. M. 166 Abbayes H. D. 127 Abbond J.-L. M. 7 Abboud M. M. 394,412 Abe K. 386 Abeles R.H. 432 433 434 435,442 Abramovitch A. 136,176,382 Abramovitch R.A. 108 109 Achari A,. 17 Achiwa K. 121 205 Acton N. 303 Adachi I. 365 Adam W. 169 170,258,282 Adams D. R.,184 Adcock W. 151,216 Adembri G. 263 Adler A. E. 20 Adler V. E. 369 Adolin G. 278 Adzima L. J. 261 Agopian G. K. 239 Agranat I. 230 Aguiar A. 158 Ahlers H. 151 Ahlrichs R.,148 Ahman F. 441 Ahmed S. I. 444 Ahr A.-J. 114 Ahrens E. H. jun. 419 Aihara J.-i. 215 Aihara Y. 378 Airey J. E. 265 Aizenshtat 7. 125 Akhtar M. 394,409,412,432 Akimoto T. 273 Akiyama S.247 249 291 Alange G. G. 270 Alberti F. 300 Alberts A. W. 440 Albery W. J. 437 Albinati A. 13 Albizati K. F. 140 Albright T. A. 265 Alder R. W. 281 Aldrich J. R. 370 Alewood P. F. 108 Al-Hazimi H. M. G. 401 Aliwi S. M. 90 Allegra G. 13 Allen L. C. 297 Allinger N. L. 297 Allison D. A. 216 Alonso M. E. 201 Alper H. 109 127 129 243 Alvernhe G. 274 Alworth W. L. 423 Alzerreca A. 258 Ambrose M. C. 445 Ambrosius P.M. M. 269 Amemiya T. 245 Amin S. G. 252 Ammon H. L. 13 Amouroux R.,187 Anastassiou A. G. 276 285 Anbar M. 10 Anderson A. G. 227 Anderson L. 347 Anderson R. C. 364 366 Anderson R.D. 39 Anderson R. J. 386 Anderson W. G. 173 Ando T.368 Ando W. 114 117 148 Andrade J. G. 147 Andreeva M. A. 261 Andrews G. D. 69 172 305 306 Andrews L. J. 226 Andrieux C. P. 161 Andrieux J. 124 Andrus W. A. 325 Aneshansley D. J. 374 Anet. F. A. L. 272 296 360 Anex B. G. 22 25 32 37 39 Angerbauer R. 350 Angres I. 100 Angyal S. J. 343 Anh N. T. 190 Anjo D. M. 144 Ankner K. 161 Annis G. D. 127 335 Ansell H. V. 230 240 Ansell J. M. 381 383 Anselme J.-P. 109 Apeloig Y.,136 Appel R.,258 Arai H. 273 Arai M. 327 Arakawa S. 253 Araki Y.,364 Aranda G. 363 Aratani M. 242 Aratani T. 299 Archibald J. L. 420 Arentzen R. 355 Arias I. M. 440 Arigoni D. 410 425,427 447 Ari-Izumi A. 327 Armand J. 162.Armarego W. L. F. 282 Armitage I. M. 424 425 Am H. 368 379 Arnarp J. 356 Arndt H. C. 287 387 Arnett E. M. 48 85 202 Aronowitz Y. J. 22 Arsura E. 368 Asao T. 244 Asaoka M. 330 Ashby E. C. 141,146,309 Ashe A. J. 278 Ashkenazi P. 246 Ashworth B. 100 Ashworth R. W. 218 Asirvatham M. R. 154 Askari M. 295 297 Atkins P. W. 90 Atkins R. J. 171 Atkinson R.S. 107 109 Atsumi K. 260 Attia S. Y. 189 Attinti M. 223 Atzmiiller M. 235 Aue D. H. 86,297 Aumann R. 127 Ausloos P. 7 Au-Yeung B.-W. 136 Awad S. B. 109 Ayalon-Chass D, 331 Ayediran D. 228 Ayer W. A. 374 Ayscough P.B. 103 Azami T. 7 Azegami I. 260 Azogu C. I. 109 Baasner B. 63,249 Baba H. 23 30 Baba S.384 Babiarz J. E. 258 Babler J. H. 382 387 Babsch H. 218,279 Babson J. 433 Bacher A. 39 Bachler V. 60 Bachman G. L. 122 Back T. G. 336 Backinowsky L. V. 347 Backlund S. J. 144 149 332 Backvall J.-E. 192 Baggiolini M. 379 448 Bagus P. S. 110 Bahl J. J. 300 Bailey B. K. 369 Bailey F. C. 319 Bakalik D. P. 102 Baker D. C..353 Baker E. W. 19 Baker R. 134 185 367 379 390 Baker T. C. 369 377 378 Balchunis R. J. 235 Baldwin J. E..64,69,172,260 285,305,306,340 Baldwin J. M. 43 1 Balke D. E. 31 Balthazor T. M. 261 Balyeat J. R. 117 Bamford C. H. 90 Bamkole T. O. 228 Banasiak D. S. 147 Banda F. M. 154 Bandura A. V. 45 Banerji A. 265 Banet D.M. 311 Bangerter F. W. 436 Banister A. J. 270 Banno K. 326,381 Banoub J. 344,346,347 BanweII T. 225 Barak A. V. 370 Barbadoro S. 259 Barber G. N. 285 Barber W. 295 Bard A. J. 162 Barden R. E. 440 Barfield C. S. 376 Barker D. A. 344 Barker J. M. 282 Barlos K. 143 Barltrop J. A. 173 Barnard G. F. 394,409 Barnett J. W. 224 Barras S. J. 378 Barrett A. G. M. 312 349 Barrett J. 417 Barron P. F. 142 Barsotti R. 43 Bartell R. J. 368 Bartels-Keith J. R. 271 Bartlett P. A. 200 324 Bartmess J. E. 85 86 140. 202 Bartoli G. 227 264 Barton D. H. R. 124 173 213,229,270,312,314,325 341,349,358,359,361 Barton T. J. 147 Basha A. 208 Basilevsky M. V. 59 Basolo F.109 Bass R. G. 116 Basset J. M.,119 133 185 304 Bassindale A. R. 151 Bates D. L. 445 Bates G. S. 336 Bates R. B. 300 Batlle A. M. del C. 396 Bats J. W. 12 Battersby A. R. 393,396.397 398,399,400,401,402,404 405,407,411,413,417,419 424,425,427 Batzold F. H. 433 Baudoir J. L. 13 Baudoug R. 336 Bauld N. L. 68 298 Baumgartel O. 292 Baumstark A. L. 341 Bausch J. 398 Bauschlicher C. W. jun. 110 Bayles R. 236 Beak P. 139 282 Bean G. P. 282 Beard B. 377 Beaucage S. L. 354 Beauchamp J. L. 85.88 Beavers W. A. 300 Beck J. F. 398 Becker H. D. 279 Becker K. B. 310 Becker R. S. 31 32 Beckhaus H.-D. 180 Beckmann B. G. 222 Bedard W. D. 372 Beer R. J.S. 268 Beevor P. S. 368 Begley M. J. 294 334 377 Beheshti I. 169 193 Behrens U. 253 Beier B. F. 135 Belcher R. V. 411 Belkind B. A. 262 Bell A. A. 190 377 Bell B. 270 Bell L. 48 Bell W. J. 386 Bellas M. 220 Bellus D. 65 290 Belzecki C. 197 198 Benati L. 112,253 Bendig J. 237 Benedetti E. 122 Benisek W. F. 439 Benitez F. M. 112 Benjamin D. M. 377 Benn F. R. 68 192 Benn M. 199 Benn M. H. 375 Bennett J. A. 30 Bennett J. E. 101 Bennett M. J. 374 Bensel N. 202 Benson A. M. 439,440 Benson B. W. 108 Benson S. W. 101 Bente P. F. 5 Bentley T. W. 71 Author Index Bentor Y.,230 Bentrude W. G. 100 Benu M. 108 Bercaw J. E. 220 Berchtold G. A. 218 Bergbreiter D.E. 141 204 Berger D. 201 Bergman R. G. 63 65 113 217,220,297,308 Bergmann K.-H. 427 Berg-Nielsen K. 110 Bergstrom G. 372 Berisford C. W. 368 Berk H. C. 216,294 Berkovitch-Yellin Z. 12 Berlin K. D. 282 Berliner E. 178 Berman H. M.,17 Bernard D. 131 Bernasconi C. F. 228 Bernauer K. 255 Berndt A. 298 Bernhardt J. C. 175 229 Berning W. 170 Bernstein H. J. 33 Beroza M. 369 Berry J. M. 356 Berry J. P. 189 Berthod H. 50 Bertrand M. 184 318 Bertsch K. 182 Best G. 268 Bestmann H. J. 181,369.383 385 Bethell D. 99 Bettolo R. M. 159 Beugelmans R. 282 Bewick A. 156 Beyermann M. 237 Beynon J. H. 3 7 9 Bhatnagar S. P. 184 Bhatt R. S. 355 Bhattacharyya S.336 Bianchi M. 122 Bickart P. 137 Bickelhaupt F. 218 233 Bidan G. 168 Bieber W. 234 Bielski R. 312 349 Bieri J. H. 255 Bierl B. A. 375 Biggs I. D. 237 Bilhou. J. L. 133. 185 304 Billingham N.C. 180 Billingham R. C.. 309 Billings R. F. 372 Billman W. 383 Billups C. 34 Billups W. E. 114,286,287 Binger P.,301 Binkley J. S. 136 Binkley R. W. 352 Binkley W. W. 352 bin Samsudin M. W. 171 Author Index 449 Birch D. J. S. 28 Boon-Keng Teo 163 Brinkmeyer R.S. 205 Birch M. C. 372 Boontanonda P. 302 Britton L. N. 378 Birge R. R. 30 31 Booth B. L. 99 Brock. D. J. H. 433 Birks J. B. 28 Boppre M. 367 Brocklehurst K.,432 Birnbaum G. I. 296 Borchers F. 5 6 Brockmann H.,jun.421,423 Bischof P. 299 301 Borden J. H. 372 Broekhof N. 277 Bischofberger K. 348,349 Borden W. T. 68.293 Broer W.J. 5 Bishop S. W.,223 Bordwell. F.G. 86 Bromilow. J. 217 Black T. G. 359 Borer R. 207 Brooks. C. J. W. 439 Blackburn E. H. 443 Borhani K.J. 162 Brooks D. W.. 246,290 Blackburn T. F. 322 Borromeo P.S. 186 203,,313 Brown C. A. 143,176,316 Blacklock T. J. 166 167 Borst P. 446 Brown F. J. 9 Blair A. S. 5 Boscher J. 376 Brown H. C. 71 72 81 142 Blair L. K. 85 Bose A. K. 202 252 143 188 190,282,320 Blakeney A. J. 286 287 Bosnich B. 120 Brown J. N.. 37 Blankenship R. M. 294 Boswell. R. F. 116 Brown R. D.,60 Blauer G.. 25 Botta M. 196 Brown,R. F. C. 118 Blight M. M.,372 Botteghi C.. 122 Brown W. V. 371 Blah K. 433 Boulares L. 162 Brownbridge P.,211 Blomberg C.141 Bouma W. J. 63 Browne A. R. 238 Bousch G. M. 376 Browne L. E. 372 Blount J. F.,194 265 Bloxham D. P. 433 Bovill M. J.. 180 Browne L. J. 289 Blum J. 106 125 Bowden B. F. 239 Browne L. M. 374 Blum L. 229 Bowen R. D. 4,s Brownlee R. T. C. 217 Blum M. S. 370,372,374 Bowers M. T. 86 297 Brownstein S. 180 Blum R. B. 326 Bowers W. S. 371 373,3 78 Bruce M. I. 119 Blumenfeld J. 122 Bowman D. F. 98 Bruck D. 216 Blunt J. W. 296 Boxer S. G. 20 Bruder H. 126 Boatman R. J. 138 222 Boyd D. R. 174,197 Bruckner J. 13 Bobbitt J. M. 157 Boyd G. V. 270 Bruntrup G. 312 Bobek M. 359 Boyd R. J. 113,297 Bruggemann-Rotgans I. E. M. Bobkova R. G. 282 Boyd R. K. 9 373 Boche G. 69 Boyer F.,398 Bruice T. C. 434 Bochmann M.,262 Boyer J.H. 265 Bruins A. P. 8 Bocian D. F.. 296 Bracke J. W. 378 Brunet J. J. 179 Bock H. 268 Bradford K. C. 173 Brunsvold W. R. 130 Bockhoff F. M. 5 Bradlow H. L. 437 Bruza K. J. 331 Bodart-Gilmont J.. 254 Bradshaw J. W. S. 379 Bryce-Smith D. 171,219,220 Bode W. M.,368 Bradshaw R. A. 440 Brylikowska-Piotrowin J. Bodkin C. L. 343 Bradsher C. K.,60 321 Bodoev N. V. 237 Brady P.A. 240 Bryson T. A. 211,221,331 Boeckman R. K. jun. 111 Brady U. E.. 368 Bubb W. A. 270 331 Braekman J. C. 367,372 Bucciarelli M. 197 Bohme P.. 199 Brautigam I. 200 Buchanan G. W. 296 Boekelheide V. 234 Brautigam K.-H. 200 Buchanan J. G. 348 Boelens H. 338 387 Brand J. M.,372,378 Buchardt O. 174 273 Boelhouwer C. 133,185 Branz. S.E. 64 Buckel. W. 410 Bogdanowicz M. J. 287.387 Braslavsky S.110,282 Buckley D. G. 402 Bogorad L. 396 Braterman P. S. 127 Buckwalter B. L. 201 Bohandy J. 19 22 Brauer O. 355 Budzikiewicz H. 239 Bohlen P. 436.437 Brauman J. I. 85 87 Buchel K. H. 264 Bohm H. 116 Bregman R. 226 Buchi G. 187 Bohme D. K. 85,87 Breslow R.,242,347 Buehring M. 372 Bolewska K. 14 Brestkin P. A. 177 Buenker R. J. 27 Bolin D. R. 173 Brettle R. 154 Bug J. E. 280 Bolis G. 44 Breuer A. 168 Buhl H. 112 Boller E.F. 377 Breuer E. 311 Bukin V.N. 427 Bolton R. 230 Brewer A. 239 Buldain G. 401 Bon M.,271 Brewster P.D. 222 Bullock E.,396 Bonaccorsi R. 46 Briat B. 25 Bullpit M.,216 Bonini B. F.,269 Bridges A. J. 289 Buncel. E.,228 Bonneau R. 165 Briggs N.H. 226 Bundle D.R. 344 Bonnett R. 11. 25 400 423 Brinker U. H.,249 291 Bunes L.196 429 Brinkmann A. 301 Bunnell C. A.. 335 450 Bunnett J. F. 227 Burden I. J. 281 Buren W. F.. 374 Burford C. 149,324 Burgada R.,271 Burger D. 375 Burger J. J. 313 Burger K.,266 Burger U. 218,302 Burgess M. T. 271 Burgstahler A. W. 386 Burke L. A. 59 Burkholder W. E. 370 Burley R.E. M. 230 Burlingame A. L. 3 Burns P. A. 258 Burns W. 302 Bursey M. M. 3 9 Burton D. J. 111 Busch J. H. 55 Buse C. T. 202 326 Buser H. R. 368 Bush C. A. 36 Bushweller C. H. 255 Butler L. I. 369 Butler R. N. 282 Butt B. A. 369 Bykhovsky V. Ya. 427 Byler R.C. 370 Byrne K. 379 Byrom N. T. 388 Cabrino R.,243 Cacace F. 82 223 226 Caddy P. 220 Cadiot P.182 Cadogan J. I. G. 98 Cahiez G. 131 319 Caillean H. 13 Caillet J. 13 Cairncross A. 306 Calas R. 192 Calderazzo F. 119 Callis P. R.,37 Cambie R.C. 189 Cameron D. W. 239 Cammaerts-Tricot M. C. 372 Campagna F. 208 Camparini A. 263 Campbell D. E. 285 Camus A. 123 Cannon J. R.,152,423 Capiua A, 368 Capon B. 75 Caporusso A. M. 126 Capozzi G. 179,253 Caramella P. 59 61 170 Card P. 238 Carde A. M. 212 368 369 386 CardC R. T. 212 367 368 369,377,386 Carey P. R.,33 Cariou. M. 77 Carlini C. 126 Carlsen P. H. J. 61 170 Carlson E. C. 377 Carmody M. J. 246 300 Carnduff J. 240 Carotenuto A. 269 Carotti A. 208 Carpenter A. T. 398 Carpita A. 384 Carr D.B. 131 146 Carr R. M. 274 Carrel] H. L. 17 Carrii R. 254 Carroll S. E. 107 Caruthers W. 232 Case M. E. 444 Casey C. P.,130 Casini G. 208 Cass J. C. 265 Cassani G. 368 Cassar L. 127 Cassara P. 436 Cassidy R. F. jun. 370 Caubere P. 105 179 Caulton K. G. 135 Cauquis G. 275 Cava M. P. 115 Cavaliero J. A. S. 41 1 Cavallone F. 43 Cavazza M. 243 Cave R.J. 65 Cavell R.G. 216 Cavill G. W. K. 374 Cerfontain H. 225 226 Cernigliaro G. J. 383 y86 389 Cessac J. 68 298 Chabaud B. 275 Chadwick D. J. 260 Chae Q. 25.30 32 Chaloupka S. 255 Chamberlain W. T. 286 Chambers D. 189 Chambers D. L. 376 Chambers J. Q. 157 Chambers 0.R.,109 Chambers R. D. 174 Chan B.G.. 377 Chan K.-K.,202 Chan T. H. 117 187,385 Chandross E. A. 239 Chang C.-S. 73 Chang Y.-H. 285 Chantrapromma K. 66 Chapdelaine M. J. 319 Chapman D. 32 Chapman 0.L. 92 Chapman R.A. 420 Chappell I. 68 192 Chapya A. 377 Chaquin D. 388 Chaquin P. 168 Charbonneau G. P. 13 Charles G. 196 Author Index Charles H.C. 239 Charmillot P. J. 379 Chatt J. 109 Chattha M. S. 158 Chau M. M. 261,277 Chaudhry I. A. 415,417 Chaudhury M. F. B. 375 Chawla B. 48 Chawla H. P. S. 252 Chellathurai T. 108 109 Chen B. 137 Chen H. H. 35 Chen S. J. 262 Chen T. B. R. A. 313 Chen W. Y.,265 Cheng L. D. 22 Cheng P. T. 75 Cheng Y. Y.,161 Cheong K. K. 37 Chern C.-I.322 Cherry R.J. 32 Chertkov V. A. 327 Cheung Y. F. 441 Chheda G. B. 17 Chiang C. C. 14 Chiang C.-S. 222 Chiang W. 171 Chiao J. P. 441 Chiasson B. A. 218 Chiba T. 155 Chiellini E. 110 Childs R.F. 215 290 Chin C. A. 23 24 Chisholm M. D. 368,369 Chittattu G. 206 335 Chiu S.-H. L. 347 Chivois A. B. 19 Chmielarz B. 234 Cho. H. 390 Chong A. O. 365 Chong. L. 372 Choplin F. 64 Chou K. J. 201 Chow M.-F. 170 Christensen J. J. 174 273 Christensen R.L. 27 28 30 Christoffersen R. E. 19 Christoph G. G. 216 238 Chuankamnerdkarn M. 276 Chuche J. 69 254 Chudek J. A. 246 Chueng M. 441 Chuisoli G. P. 125 Chuit C. 189 Chwang T. L. 177 Chwang W. K. 189 Ciardelli F.126 Cimiraglia R.,68 Ciranni G. 223 Clardy J.,61,68,216,261,375 Clark D. T. 52 Clark G. 130 Clark J. H. 204,244,339 Clark L. B.. 35 Author Index Clark M. G. 433 Clarke F. M. 446 Clarke M. T. 220 Clarke T. C. 63 Claveni P. 13 Clayton R. K. 24 Cleland W. W. 442 Clemens A. H. 225 Clementi E. 43,44 Clennan E. L. 163 Clezy P.S. 408. 415 417 Clive D. L. J. 206 312 335 Clode D. M. 357 Closs G. L. 20 Coates R.M. 235 Cockrum P.A. 369 Coggins J. R. 444 Coghlan J. M. 387 Cohen B. J. 139 Cohen T. 223 Coke J. L. 317,387 390 Cole T. E. 323 Collins J. 302 Collins P.M. 362 364 Collman J. P.,431 Collonges F. 313 Comins D. L. 276 Comisarow M.89 CommerGon A. 141 Cone C. 7,245 Conlon M. 98 Connelly N. G. 126 Conner W. E. 374 Connert J. 375 Connon H. A.. 302 Consiglio G. 228 Conti C. 386 Cook D. 82 Cook M. J. 263,273 Cooke F. 149,324 Cooke M. P. jun. 128 139 330,340 Cooks R. G. 3,7 8,9 10 Cookson R.F. 265 Coombes R. G. 224 Cooper A. J. L. 435 Cooper C. M. 74 Cooper J. W. 97 99 100 Cope B. T. 419,429 Copenhafer R. A. 158 Copland D. 245 260 Coppel H. C. 371 Coppens P. 12 Corbin V. L. 367 368 Corcoran J. W. 336 Corey E. J. 321 326 366 Cornforth J. W. 410,413,419 Cornforth R.H. 413 Cornu H. 3 Corrigan D. A. 163 Corriu R.J. P. 149 Corwin A. H. 19,396,406 Cory R.M. 112,341 Costa L. C. 182 Costopoulos M.G. 78 241 Cottingham A. B. 66 Cotton T. M. 23 Couch P.W. 411,415 Coughlin D. J. 169 Cousseau J. 178 Coutrot P. 314 Cowherd F. G. 331 Cox B. G. 208 Cox D. J. 443 Cox D. P. 151 Coxon A. C. 281 Coxon J. M. 296 CrabbC P. 181 336 Crabtree R. H. 123 Craik D. J. 217 Craine L. 223 Cram D. J. 281 Crampton M. R.. 227 Crandall J. K. 313 Craven B. M. 16 Creaser I. I. 281 Creighton T. E. 443 Cremer D. 298 Cresp T. M. 247 248 249 29 1 Crewe R. M. 374 Crimmin M. J. 134 185 Cromartie T. H. 433 Cromarty B. J. 52 Crombie L. 377 Crosby G. A. 139 Cross J. H. 370 Crossland N. M.. 168 341 Crowe D. F. 365 Crumbie R.L. 320 Csacsko B. 305 Cu A. 236 Cueto O.258 Cuingnet E. 234 Culvenor C. C. J. 369 Cunico R. F. 63 Cunningham A. J. 85 Cuppen T. J. H. M. 174,240 Curtin D. Y. 14 15 Curtis M. D. 134 Curtis W. D. 281 Cusmano G. 268 Cussans N. J. 325 Cuvigny T. 203 Czarny M. R.,108 Dach R.,195 Dagan A. 216 Dahl L. F. 163 Dali H. M. 238 Dallatomasina F. 125 Daloze D. 367 Dalton J. 87 Daly R. F. 324 Damji S. W. H. 227 Dan N. 242 d’Angelo J. 126,140,221,325 Danilov V. I. 36 45 1 Danishefsky S. 232 289 Dannenberg,J. J. 49 Danson M. J. 445 Dao L. H. 269 Daray R.,98 Darby N. 247 Das K. G. 7 Das P. K. 31 Dattaguysta J. K. 14 Daub J. 245 Daum H. 174 Dauner H.-O. 404,424 Dauplaise D. 261 David S.350 363 David S. M. 364 Davidson A. 20 Davidson A. H. 186 Davidson B. E. 443 Davidson N. 35 Davidson W. R.,297 Davies J. E. 11 429 Davies L. B. 272 Davies S. G. 218 296 Davis J. H.,65 106 113 118 217,297,308 Davis R. E. 168 239 Davis W. H. jun. 222 Day A. C. 173 Day P.,24 Day R. A. 324 Deakyne C. A. 297 De Anngelis F. 196. De Bruin K. E. 210 de Camargo J. M. F. 372 Declerq J. P. 240 254 de Duve C. 446 Deeg R.,427 Defay N. 240 241 Defaye J. 353 de Fonseka K. K. 64,231 De Frees D. J. 216 Degenhardt C. R. 149 187 216,294,312 Degrand C. 158 159 Dehmlow E. V. 110 Deininger D. 49 138 De Jeso B. 196 De Jongh D. C. 105 Dekkers H. P. J. M.. 169,258 Del Alley W.100 de la Mare P.B. D. 226 De La Mater M. R.,223 de Las Heras F. G. 248 Delaunay L. 273 de la Vega J. R.,55 Del Bene J. E. 57 Dtltris G. 192 Dellaria J. F. jun. 223 Dell’Erba C. 240 Delley B. 379 De Lue N. R. 143 Delugeard Y.,13 De Mairena J. 433 de Maria P. 208 de Mayo P. 167 de Meijere A. 305 323 De Meyer C. 4,7 Demitras G. C. 134 De Moss J. A. 443,444 Demou P.,425 Dennis R. W. 99 Denny C. T. 174,273 Deno N. C. 181 Deol B. S. 332 Derguini-Boumechal F. 141 De Rossi R. H. 228 Derrick P. J. 3 Deschamps B. 311 Descoins D. 383 Desimoni G. 60 Desirajin G. R. 15 Destro R. 12 253 Desucher J. 13 De Titta G. T. 16 Detre G. 365 Detsina A.N. 225 Detty M. R. 219 Devaquet A. 68 Devilbiss E. D. 375 Deville C. G. 170 Deville C. S. 61 Devlin J. L. tert. 216 De Vries R. A. 120 de Waard E. R. 313 Dewar M. J. S. 7,65,68 145 169,241,245,298 de Wolf W. H. 218,233 De Young S. 178 Deyrup J. A. 262 Diakiw V. 415,417 Diamond J. 28 Diaz A. F. 161 163 Di Cesare P. 346 Dietz A. G. jun. 223 Dietz R. 130 Di Gregorio S. 99 Dill J. D. 136 Dillon P. W. 68 Dilworth J. R. 109 Dirks G. W.,282 Disselkoetter,H. 379 Dittmer D. C. 258 Dixit D. M.,213 Dixon H. B. F. 432 Dixon W. T. 101 Djerassi C. 9 25 Dmytraczenko. A. 362 Dobashi. s.,168 Dobbie R. C. 99 Dobbin C. J. B. 269 Doddrell D. 142,216 Dolak T.M. 211 331 Dolbier W. R. jun. 231 Doleschall G. 323 Dolgushin M.D. 47 52 Dollat J.-M. 181 Dollimore D. 94 Dolphin D. H. 20 Domelsmith L. N. 59 Dondoni A. 252 Donelson D. M.. 221 Donovan D. J. 81 Donovan S.F.. 336 Doolittle R. E. 369 370 Dopheide T. A. A. 443 Doria M.-C. 331 Dorie J. 208 Dotz K. H. 130 Dougherty D. A. 150 Dougherty R. C. 87 Dowle M.D. 208 Doyle M. P. 188,223,313 Draggett P. T. 126 Draxl K.,3 Driguez H. 344 Drozd V. N. 227 Drucker G. E. 86 Druey J. 66 Dryhurst G. 156 Dubois J.-E. 84 177 206 Duboudin J. G. 105 Duchet D. 345 Dueber T. E. 76 Dunnbier K. 269 Diirr H. 267,268 Duesler E. N. 261 Duffey S. S. 370 Duffield R. M.372 Duhamel L. 140 Duhl-Emswiler B. 212 386 Dumas-Bouchiai J. M. 161 Dumont W. 212 Dunaway-Mariano D. 276 Dunbar R. C. 7 Duncan D. P. 148 Dunford J. A. 176,319 Dunkelblum E. 165 Dunkin I. R. 174 273 Dunn A. D. 348 Dunn L. C. 245,260 Dunogues J. 180 192 Du Priest M.T. 195 DurCault A. 243 Durette P. L. 355 Durner G. 314 Dun H. 111,114 Dussauge A. 113 Dwyer J. 68 192 Dyck V. A. 368 Dymerski P.P.. 5 Dyong I. 365 Ealick S.E. 14 Earnshaw C. 186 187 321 Eastwood F. W. 118 Eaton W. A. 21 38 39 Eberbach W. 69 Eberhard W. G. 376 Eberson L. 155 Eberstein K. 353 Author Index Ebine S. 244 Ebrey T. G. 24 Eby R. 346 Echegoyen L. 163 Echigo Y. 251 Echigoya E.133 Eckell A. 61 Eckert R. 25 Eckhardt G. J. 25 Edgar A. R. 348 Edgar J. A. 369 Edge D. J. 95,99 101 Edmiston J. F. 369 Edmonds J. S. 152 Edmondson D. E. 39 Edwards G. J. 156 Edwards J. H. 192 Edwards L. 20 Eggelte H. J. 169 Eggerer H. 410 Eggimann W. 228 Eguchi S. 116 Ehlinger E.,149 324 331 Ehrlich S.,178 Eichenauer H. 204,338 Eimerl S.,443 Eisch J. J. 145 Eisenstein O. 60 190 Eisner T. 374 375 Eitelman S. J. 348 349 351 Eiter K. 379 Eklind K. 359 El-Abbady,S. 273 El-Deek M. 282 Elder G. H. 401 407 408 Elder J. F. 7 9 Elgavi A. 252 Eliel E. L. 272 Ellery J. C. 443 Elliger C. A. 377 Elliot A. J. 90 103 Elliot J. D. 213 Elliot R.M.9 Elliot W. J. 389 Elliott I. W. jun. 155 Elliott R. C. 223 Ellis B. S. 183 211 Ellison G. B. 300 El-Sayed M.A. 29 Elson I. H. 99 El'tsov A. V. 230 Elving P. J. 153 Enders D. 195 204,338 Endo A. 436 Endo K.,433 Endo Y. 229 Engel J. 16 English T. H. 103 Enkaku M. 248 Ephritikhine M. 303 Erdtman H. 280 Erman M.,16 Ernest I. 117 Erwin V. G. 433 Author Index Eschenmoser A. 423,426 Essenbreis H. 375 Evans D. A. 325 367 378 379,390,398,399 Evans D. H. 160,163 Evans G. T. 90 Evans N. 407 Evans R. H. 194 Evans S. 6 9 265 266 Evans S. L. 372 Evaresto R.A. 45 Eweiss N. F. 252 Ewing B. 372 Ewing D. F. 216 Ewing G. D. 215,216,294 Eyring H.37 Faehl L. G. 295 Fahrni H.-P. 243 Fairhurst S. A. 99 Fales H. M. 370 374 Falk J. E. 392 Fall R. R. 440 Falou S. 126 140 221 Falsig M. 162 Fanconi B. 37 Faragher R. 266 Farcasiu D. 116. 223 Farnum D. G. 212,280,386 Farook S. 423 Fedeli W. 13 Fedorynski M. 110 Fein A. 444 Feinstein G. 399 Feldmann J. 365 Feldstein A. C. 191 Felkin. H. 66 189 Felman S. W. 197 338 Felstein G. 383 Felton R. H. 22 Fenner H. 434 Ferguson G. 302 Ferguson J. A. 163 Feringa B. 185 Ferramola A. M. 407 Ferrer-Correia A. J. V. 10 Ferrier R.J. 351 359 Ficini J. 126 140 221 243 Field D. J. 64 Filippo J. S.,322 Filler R. 282 Filosa M. P. 286 Finn W. E. 378 Fiorentino M.227 Fioshin M. Ya 153 Firestone R. A. 59 110 Fischer H. 101 151 167 430 Fischer J.-C.,352 364 Fischer P. 147 Fisher C. 121 Fisher J. 433 Fishwick B. R. 183 211 Fitjer L. 294 Fitzgerald T. D. 369 Fitzsimmons B. 150 Flammang. R. 4,7 Flatow A. 233 Fleet G. W. J. 322 Fleming I. 136 186 Fleming M. H. 369 Fleming M. P. 185 Flicker W. M. 29 Flint H. M. 377 Flood T. C. 324 Florent J.-C. 359 362 Floyd M. A. 378 Foa M. 127 Forster H. 232 Forster S.,39 Folwell R. 375 Fomum Z. T. 184 Fonken G. J. 307 Fookes C. J. R. 405,417 Foos J. S. 64 307 Ford G. P. 65,68 Ford W. T. 61,69 Forey D. E. 377 Forni A. 197 Forster L. S. 36 38 Forsyth D. A. 80 Forte P. A.227 Fortier S. 11 Forster M. S. 85 Foster R. 246 Foti F. 264 Foucaud A. 107 Fox D. P. 118 Fox J. J. 348 Fox J. L. 38 39 Fox M. A. 306 Foxall J. 101 Fowler L. J. 436 Frackowiak D. 39 Frahn J. L. 369 Frajerman C. 66 189 Francesconi K. A. 152 Franck B. 397 Franck R. W. 238 Francke W. 372 Franck-Neumann M. 62 113 267 Francotte E. 254 Frandsen E. G. 268 Frank A. 236 Fraser R. R. 391 Fraser-Reid B. 349 363 364 365,366,389 Fray G. I. 171 Fredericksen,S. 4 Frediani P. 122 Freeman J. P. 266 267 Freeman P. K. 110 117 Freer A. A. 11 Freidlina R. Kh. 90 Frey H. M. 61 Fried J. 389 Friedman H. S. 278 Friedrich E. 327 Friesen M.D. 6 Fringuelli F.282 Fritchie C. J. 39 Fritz H.? 218,244,279 Frolich S. 11 1 268 Fromm J. 43 Froyen P. 382 Fruehey 0.S.,318 Frydman B. 398 399 400 401,403 Frydman R. B. 398,399,400 401.403 Fryer R. I. 265 Fryzuk M. D. 120 Fu P. P. 238 297 Fu Y. C. 37 Fu Y. L. 359 Fucaloro A. F. 36,37,39 Fuchikami T. 126 148 Fuchs P. L. 335 Fugedi P. 358 Fuhlhuber H. D. 279 Funfschilling J. 22 Fueno T.,155 Fugate R. D. 24 Fuhrhop J.-H. 428 Fuji K. 331 Fujimori M. 63 245 Fujimoto H. 64 Fujino S. 278 Fujise Y.,244 Fujita E. 236 331 Fujita K. 112 Fujita M. 30 Fujiwara K. 224 Fukami H.. 367,368,371 Fukami J. 368 Fukazawa N. 246 Fukui. H. 370 Fukui K. 55,64 107 247 Fukumoto K.10 190 314 Fukumura M. 108 Fukunaga T. 300 Fukuyama Y. 336 Fukuzumi S. 92 93 Fung C. H. 441 Fung M. M. 24 Funk R. L. 126,314 Furakawa J. 126 Furakawa N.,108 Furneaux R. H. 351,359 Furusaki F. 282 Fusco F. 236 Fyfe C. A. 226,227 Fyles T. M. 238 380 384 Gabhe S. Y. 223 Gadelle A. 353 Gagne R. R. 431 Gais H.-J., 205 Gal J. Y. 8,163 Galbraith M. N. 390 454 Gale R. 20 Galeaui E. 331 Gallagher E. M. 369 Galle J. E. 145 Gallenkamp B. 70 Galli C. 205 Gallois M.,383 Games D. E. 407 408 411 415 Gamliel A. 247 Gan T. H. 217 Gandour R. W. 61 170 Ganguly A. K. 366 Gantz D. 397 Gara W. B. 97 Garbers C. F. 382 Garcia B. A. 318 Gardlik J.M. 215 Gardy E. M. 101 102 Garegg P. J. 345 354 359 Gargano M. 123 Garnett J. L. 94 Garrett V. H. 377 Garrison P. J. 327 Gartner B. 434 Gartshore D. 216 Gase R. A. 194 Gassman P. G. 133 185,207 235,332 Gaston L. K. 379 Gatmaritan Z. 440 Gautier A. 123 Gavezzotti A. 46 Gavin R. M. jun. 27 Gavrilov L. D. 180 Gawley R. E. 285 Gearhart R. C. 266 Gedge D. R. 334,336 Gehlhaus J. 375 Geiss K.-H.,212 Geittner J. 60 Gell K. I. 243 Gender A. 248 Gentric E. 270 George B. 252 George M. V. 61 Georgopapadakou N. 424 Gerber U. 255 Geresh S. 122 Gerken B. 372 Gerlach H. 336 Germa H. 271 Germain G. 240 254 Gessner M. 238 Getman D. 113,166 Geue R.J. 281 Gewitz H.-S. 417 Ghisla S. 433 Ghriofa S. N. 98 Giacomelli G. 126 Giacomello,P. 82 223 226 Giacovauo G. 11 Giam C. S. 128 Giannoccaro P. 123 Gibson H.W. 319 Gibson K. H. 398 399 Giese B. 180 217 Giffney. J. C. 224 Giglio E. 13 Gil G. 184,318 Gilb W. 234 Gilbert A. 171 219 220 Gilbert B. C. 91 92 95 96 97,100,101 Gilbert K. E. 305 306 Gilbert S. G. 17 Gilchrist,T. L. 266 Giles N. H. 444 Gilgen P. 172 282 Gill G. B. 68 192 314 Gillan T. 98 Gilman S. 320,335 Gilmore C. J. 11 Ginebreda A. 110 Gingrich H. L. 262 Ginsberg R. J. 149 Ginsburg D. 246 Giordano C. 79,123 Giovannini E. 221 Girgenti S. J. 276 Gladiali S. 122 Gladieux N. 359 Gladysz J.A. 233 Glaser R. 122 Gleiter R. 299 301 Glidewell C. 150 Glover S. A. 229 Glusker J. P. 17 Glyde E. 223 Goddard W.A. 106,113 118 256,297 Godfrey J. M. 25 Godfrey M. 217 Goel A. B. 141 Goerdeler J. 269 Goering H. L. 73 Goffin E. 208 Gohee Y. 275 Gokel G. W. 229 Goldenberg S. 368 Golding B. T. 425 Golding J. G. 224 Goldschmidt,E. 235 Goldstein M. J. 69 307 Goldwasser,J. M. 213 Golob N. F. 287 Gonnermann J. 200 Gordon M. D. 300 Gordon M. S. 241 Gore W. E. 372,389 Gorelik M. V. 239 Gorman J. E. 370 Gorringe D. M. 446 Goswami R. 139,340 Gotoh H. 109 Gotoh N. 280 Gotthamrner B. 359 Gouesnard J. P. 208 Author Index Gouin L. 178 Gouterman M.19 20 21 22 Gouverneur P. 223 Grabe B. 40 Grabley F. F. 321 Grabley S. 255 Gradushko A. T. 20 Graf R. 147 Gragerov I. P.,98 Graham R. 6 Grahnen A. 440 Grande H.J. 445 Granick S. 417 Grassi G. 264 Graves K. L. 379 Gray J. R. 377 Graydon W. F. 133 185 304 Grayson J. I. 186 Graziano M. L. 269 Greany P. D. 376 Greaves M. F. 442 Grebenkina V. M. 230 Gree R. 254 Green F. R. 111 200 324 Green M. 126 220 Green M. L. H. 303 Green M. M. 9 Greenberg A. 285 Greenblatt R. E. 370 Greene A. E. 336 Greene J. 134 Greenhouse R. 68 293 Greeves D. 366 Gregory B. H. 281 Greif N. 67 149 Gresh N. 50 Gribble G. W. 237 Grieco P. A. 320 335 338 Grierson J. R.339 Griffin A. C. 169 Griffin G. W. 239 Griffith R. C. 276 Griffiths G. 183 211 Grigg R. 302 388 Grima J. P. 64 Grimm K. G. 325 Grobel B. T. 140 331 Gross B. 346 Gross S. R. 444 Grout A. 83 Grovenstein E. 66 Grubbs R. H. 120 132 Grudyushko A. T. 20 Griitze J. 233 235 Gruntz U. 196,252,334 Grunwell,J. R. 112 Gruska. R. 238 Guanti G. 240 Giinther H. J. 289 Gunther M. 361 Giinthert P. 247 Guerin C. 149 Guest M. F. 149 Guggenberger L. J. 266 Author Index Guinot A. 182 Gunn. B. C. 276 Gunzer G. 404 Gupta B. G. B. 189 324 Gupta C. M. 348 Gupta P. C. 408 Gurke A. 233 Gustafsson K. 279 Gutman A. L. 246 Gutman I. 215 Gutschow C. 410 Guzier F.S. 321 Habraken C. L. 266 Hache K. 314 Hacker N. P.. 241 Haddon R. C. 246 Haenel M. W. 233,234 Hafner K. 62 243 Hagenbruch B. 11 1 Hager D. C. 282 Haggerty J. G. 232 Hahnfeld J. L. 111 Hai T. T. 408 Haider R. 301 Haiduc I. 137 Haines A. H. 281 Haines C. P. 368 Hijek J. 339 Hajivarnava,G. S. 353 Halbert T. R. 431 Hale G. 445 Halevi E. A. 110 299 Haley N. F. 263 Halfhill,J. E. 369 Hall C. R. 210 Hall D. 226 Hall D. R. 368 Hall J. A. 61 170 Hall L. D. 355 356,361 Hall R. H. 348 349 Halton B. 238 Ham P. J. 377 Hamada M. 365 Hamaguchi H. 323 Hamana H. 278 Hamer G. K. 151 Hamilton D. C. 167 Hammons J. H. 299 Hanack M. 75 Hanafusa T.225 Handoo K. L. 99 Hanes R. M. 323 Hanessian S. 344 346 347 366 Hansen H.-J. 65 235 236 282 Hansen. P.-E. 213 Hanson A. W. 234 Hanson L. K. 21 Hanzawa Y. 278 Harada T. 266 330 Harayama T. 390 Hardegger B. 423 Harden H. 39 Harding L. B. 118 Harding T. A. 110 Hardy T. A. 117 Harger M. J. P. 210 Hargrove R. J. 76 Harkness A. L. 419 Harless J. M. 293 Harman M. E. 109 Harman P. J. 217 Harms R. 199 Harnden R. M. 157 Harnisch J. 292 Harpool R. D. 42 Harring C. M. 372 Harris E. J. 376 Harris J. M. 75 Harris R. L. N. 370 407 Harrowfield J. M. 281 Hart H. 137 165 238 239 253 Hart I. 268 Hartke K. 208 Hartog F. A. 141 Hartshorn M. P. 179 225 Hartzell G.E. 63 Harvey R. G. 238 297 Hase H.-L. 242 Hashimoto S. 207 342 Haskell T. H. 355 Hass J. R. 9 Hassner A. 149 Haszeldine. R. N. 99 Hatanaka N. 166 Hatch R. P. 287 Hathaway B. 62 Hauptmann H. 11 Hauser J. J. 261 Hausmann M. 125 Hawley M. D. 162 Hayashi H. 275 Hayashi J. 153 Hayashi K. 142 Hayashi N. 372 Hayashi T. 119 Hayes K. S. 277 Heath R. R. 379 Heathcock C. H. 202 326 Heckert D. C. 92 Hedden R. 378 Hedin P. A. 370 378 379 Heernan V. 372 Hegedus L..119 Heger I. 404 Hehemann D. G. 352 Hehre W. J. 7 48 59 140 216,298 Heicklen J. 110 282 Heider J. 110 Heidrich D. 138 Heimbach H. 6 8 Heimbach P. 126 45 5 Heimgartner H.255 282 Heinzelmann W. 172 255 Heinzmann R.,148 Heitzmann M. 222 Hekman M. 290 Heldeweg R. F. 79 Helgte B. 155 Helgeson R. C. 281 Hellerman L. 433 Hellrnan L. 437 Hellwinkel D. 138 Helmhold R. B. 12 Helmkamp G. M. 433 Helquist P. 222 313 Hemetsb’erger H. 107 Hemingson J. A. 230 Hemley R. 32 Hemmerich P. 434 Hemsworth R. S. 85 Henderson G. N. 70 236 Hendriks K. B. 343 Hendry L. B. 373,376,377 Hengesbach J. 262 Henne A. 167 Henneke K.-W. 199 Henning R. 200 Henrici-Olivt G. 1 19 126 185 Henrick C. A. 185 367 368 380,386 Henriquez R. 222 Henson R. D. 376 Hentchoya Hemo J. 196 Herberich G. E. 262 Herbert J. A. L. 264 Hergrueter C. A. 222 Herliky J.M. 437 Herlt A. J. 281 Hermann H. 253 Herndon W. C. 60 Herron J. T. 3 256 Herron N. R. 222 Hersh W. H. 133 185 Herz C. P. 233 Hesketh T. R. 443 Hess B. A. jun. 246 Hess J. 258 Hetherington W. M. 29 Hevey R. C. 433 Heyns K. 353 365 Hiatt R. 101 Hibbert D. B. 102 Hiberty P. C. 298 Hicks D. R. 349 364 389 Hicks K. 375 Hidaka. A. 127,289 Higa T. 10 Higgins R. H. 258 Higgs M. D.,379 Hill A. S. 368 369 Hillard R. L. 105 126 220 222 Hindenlang D. M. 376 377 Hinton J. F. 42 456 Hirabayashi Y. 215 Hirai Y. 190 314 Hirako Y. 116 Hirano C. 368 Hiraoka K. 85 89 Hiroi K. 380 Hirotsu K. 61,68 Hirschler M. M. 240 Hirsekorn F. J. 135 Hirst J.228 Hisaoka M. 239 Hishina Y. 433 Hitchcock P. B. 279 Hiyama T. 112 Ho C.-T. 11 1 189 202 Ho K.S. 399,424 Ho T.-L. 323 324 332 Hoard L. G. 16 Hobbs P.D. 387 Hobolth E. 158 Hochstrasser R. M. 21 174 273 Hodgkin D. C. 423 Hodgson G. L. 396,397,402 Hofle G. 199,263,269 Hogberg H. E. 234 280 Hohne H. 355 Hoekstra M. S. 287 Honig H. 297 Horster H.-G. 243 Hoffman M. K.,6 Hoffmann H. M. R. 192,329 Hoffmann R. 208 Hoffmann R. W. 11 1 114 Hofmann G. 138 Hofmann H. 278 Hofrichter J. 39 Hogeveen H. 79 Hogg A. M. 10 Hogrefe F. 63 249 Hohl-Blumer M.,270 Holcomb W. D. 108 109 Holder N. L. 364 Hollman P. C. 433 Hollenstein R. 398 424 425 Holm K. H. 112 Holmes J.L. 5 Holmes R. G. G. 91,92,95,99 Holtkotte H. 375 Holtom G. R. 29 Holubowitch E. J. 237 Holy N. L. 203 Hong P. 130 Honig. B. 30 Honrna K. 367 Hooper E. A. 445 Hopf H. 233 234 Hoppe B. 257 Hopper S. P. 149 Hoppin C. R. 132 Horak D. V. 231 Hori A. 209 Horiike K. 433 Horiike M. 368 Horikawa H. 154 Horita H. 235 Horn B. R. 377 Horn D. H. S. 390 Horner M. 162,241 291,300 Horton D. 352 353 357 Horwitz J. 34 Hosaka K. 230 Hoshino M. 232 Hosomi A. 230,340 Houalla D. 272 Hough L. 355 Houghton E. 374 Houk K. N. 59 61 62 170 245,260 Hounshell W. D. 150 Housley M. D. 443 Houssier C. 23 Houts J. J. 161 Howard J. A. 94 Howes P. D. 183 211 Howie J.K. 161 Howse P.E. 378 Hoyt S. C. 368 Hoz S. 227 Hrib N. J. 233 Huang B.-S. 174 Huang F. 262 Huang L. 444 Hudrlik A. M. 149 319 Hudrlik P. F. 149 319 Hudson B. S. 27 28 29 Hudson C. W. 116 Hudson R. F. 60 190 Hudspeth J. P. 288 Huebrer K. 440 Hunig S. 162 170 241 291 300 Huffman J. C. 135 Hug G. 31 Hug P. 218 279 Hug W. 35 Hugelin B. 126 Huggins M.-A. 166 Hughes L. 144 Hughes N. A. 360 Hughes P. R. 372,378 Huie R. E. 256 Huisgen R. 59 60 61 69 184,253,282,285 Hulett F. M. 444 Hulshof L. A. 173,341 Hummel J. P.,150 Hunt E. 396,407 Hunter D. H. 70,334 Huntress W. T. 85 Hurst J. 401 Hursthouse M.B. 11,429 Hurter J. 377 Hutchins R. F.N. 375 Hutton R. S. 90 Huynh C.. 117 Huys-Francotte M.,208 Hvistendahl G. 4 5 Author Index Ibers J. A. 126 Icli S. 248 Ide T. 244 Iesce M. R. 269 Igeta H. 273 Ignatova N. P.,282 Ihara M. 10 397 407 424 425 Iitaka Y.,273 Iizuka K. 61 Ikeda M. 275 Ikeda T. 377 Ikeno M. 148 Illuminati G. 205 Imafuku K.,244 Imagawa T. 239 Imanaka T. 126 Imfeld M. 425 Imsgard F. 32 Inaba S. 345 Inagaki S. 64 215 Inai T. 358 Inamoto N. 217 Inazu T. 233 Inbasekaran,M. N. 274 Inch T. D. 210 Inesi A. 159 Ingold K. U. 94,98 102 180 Ingraham L. L. 24 Inokawa S. 361 Inomata M. 92 Inoue I. 326 365 Inoue Y. 117 165 290 Inubushi Y. 390 Inuzuka K. 31 Ioki Y.,92 Irngartinger H.235,242 Iroff L. D. 218 Isabelle M. E. 221 Isagawa K.,110 Iseli R. 243 Ishida T. 336 Ishido Y.,345 364 Ishii S. 367 368 371 Ishii Y.,126 141 Ishikawa K. 239 Ishikawa M. 126 148 Ishikawa N. 229 Ishiyama M. 248 Isobe T. 377 Isomura K. 107 126 Ito I. 273 Ito S. 60 244 275 Ito Y.,170 260 330 Itoh A. 207 342 Itoh K. 126 141 Itoh M. 335 Ittah Y. 106 Iversen P. E. 162 Iversen T. 354 Ives J. L. 329 Iwaki S. 378 Iwasaki T. 154 Iwata S. 54 Author Index Iwatani F. 247 Iyoda M. 291 Izawa Y. 116 Izumichi N. 61 Jackman G. P. 118 Jackman L. M. 137,325 Jackson A. H. 392 399 401 407,408,411,415 Jackson J.-A. A. 7 Jackson J.R. 411 Jackson R. A. 180,309 Jacob P.,188 Jacobson B. M. 191,441 Jacobson M. 369,376 Jacquinet J.-C. 345 Jager V. 289 Jahngen E. G. E. 323 Jain K. M. 30 Jain S. C. 17 Jakabouski A. A. 321 Jakoby W. B. 439,440 James K. J. 343,413 Janiga E. R. 266,267 Janousek Z. 208,252 Janson T. R. 419 January J. R. 162 Janzen E. G. 102 Jaouni T. 374 Jaques B. 105 Jarrell H. C. 362 Jastrzebski J. T. B. H.. 229 Jean Y.,68 11 1 Jedziniak E. J. 181 Jefferson A. M. 264 Jeffrey G. A. 52 Jemmis E. D. 140,177 Jen C. K. 19,22 Jenner P. J. 74 Jennings K. R. 9 10 Jenny E. F. 66 Jensen R. B. 4 Jentsch R. 199 Jespers J. 241 Jew S.-S. 332 Jewett D. M. 371 Jiang J. B. C.253 Jochims J. C. 181 182 J~rgensen,S. E. 4 Johansen H. 24 Johansen J. E. 32 John R. A. 436 Johnson A. W. 407,423 Johnson D. W. 402 Johnson M. 327 Johnson M. C. 236 Johnson N. A.. 100 Johnson R. A, 102 Johnson T. H. 133,185 Johnson W. L. 318 Jolidon S. 65 235 Joly M.,240 Jona R. J. 319 Jones A. 205 Kanematsu K. 61 Jones A. J. 108 180 Kanghae W. 327 Jones D. W. 61,64,.231 Kanoktanaporn S. 274 Jones G. H. 281,348 Kanzawa H. 245 Jones J. H. 213 Kapnang H. 196 Jones J. K. N. 362,364 Kapoor V.M. 205 Jones K. 427 Kapteijn F. 133 185 Jones M. jun. 218 Karich G. 181 182 Jones 0.T. G. 417 Karl W. 379 Jones P. G. 15 Karle I. L. 15 Jones P. R. 137 147 Karlsen S. 382 Jones R. A. 282 Karlsson B.280 Jones S. R. 156 Karntiang P. 281 Jones T. H. 374 375 Karplus M. 27 30 Jones W. M. 110,219,249 Kasahara T. 143 Jordaan A. 348,349,35 1 Kasai N. 13 Jordan P. M. 394 Kasha M. 38 Jorgensen W. L. 48,300 Kashdan D. S. 323 Jousseaume B. 105 Katada T. 209 Joussen R. 151 Katagiri K. 378 Joussot-Dubien. J. 165 Kato K. 55 Julia S. 110 117 Kato M. 139 Jung M. E. 137,202,204,288 Kato S. 55 156,209 318,320,322,325,326,332 Kato T. 342 390 Jung M. J. 436,437 Katritzky A. R. 196,252,263 Junino A. 184 265,272,273,275,334 Junk G. A. 368 Katsoyannos B. 377 Jurd L. 232 Katz J. J. 20 23 419 429 Jutzi P. 145 Katz T. J. 132 133 185 303 308 Katzenellenbogen J. A. 380 Kaae R. S. 379 Kauffmann T. 151 201 280 Kaappe J.440 312 Kachinski J. L. C. 302 328 Kaufmann G. 64 Kai Y. 13 Kaupp G. 166 Kaib M. 375 Kausch E. 255 Kaiser E. M. 137 Kausch M. 111 Kaissling K. E. Kavai I. 359 Kaita S. 275 Kawai S. 142 Kaji K. 257 Kawalek B. 221 Kajigaeshi S. 245 Kawamura M. 257 Kajiwara M. 399 425 Kawamura T. 96 Kakehi A. 275 Kawanisi M. 239 Kakitani H. 34 Kawano T. 366 Kakitani T. 34 Kawasaki K. 367 Kalabin G. A. 180 Kay I. T. 407 Kalinowski H.-O. 136 195 Kazarians-Moghaddam H. 336 101 Kalman A. 277 Ke B. 32 Kalman J. R. 5 Kebarle P. 85 89 Kamada M. 157 Keech D. B. 440 Kamen H. 426 Keefer R.M. 226 Kametani T. 10 190 314 Keehn P. M. 235 Kamigata N. 61 170 Keeley D. E. 287 387 Kamikawa T. 377 Keen J. H. 439,440 Kamiya Y. 102 Kees F.278 Kamiyama Y. 148,257 Kees K. L. 341 Kammula S. L. 218 Keinan. E. 200 324 Kanamaru H. 189,309 Keiser I. 376 Kanbe T. 155 Keller L. 130 Kande. A. S. 265 Kemp D. L. 9 Kane J. 262 Kempe T. 216 Kaneda K. 126 Kende A. S. 61 Kanemasa S. 245 Kennard 0..15 Kenne L. 356 Kennedy G. G. 367,368 Kenner G. W. 399,411,419 Kenny D. H. 196,252,334 Kent J. E. 217 Kern C. W. 53 Ketterer B. 440 Kevan L. 101 Khalil G. E. 21 Khan T. 123 Khan Z. U. 107 Khanna P. L. 242 Khattak R. K. 262 Khor T.-C. 216 Khuong-Huu Q. 359,362 Khurshudyan S. A. 327 Kice J. L. 261 277 Kiji J. 126 Kikuchi K. 319 Killian L. 144 Kim B. F. 19,22 Kim C. S. 265 Kim J. B. 19 Kim J. H. 115,222 Kim M.G. 262 Kim S. C. 143 Kim Y.C. 398 Kimble B. J. 3 Kimura A. 248 Kimura Y. 110 Kinberger K. 262 King,A.O. 141,175,229,317 King D. S. 174 273 King J. 31 King R. W. 249,291 Kingston D. G. I. 9 Kinkemo C. L. 336 Kinnear J. F. 390 Kirby G. W. 109 Kirk C. M. 96 97 Kirkland J. J. 429 Kirmse W. 64 Kirrstetter R. G. H. 235 Kishaba A. N. 369 Kishino K. 368 Kita J. 107 Kitagawa Y.,207,342 Kitahara Y,246,342 390 Kitamura C. 371 Kitamura T. 239 Kitasawa M. 233 Kitaura K. 51 Kitching W. 142 151 216 Kito T. 240 Kitschke B. 62 265 Kj~sen,H. 32 Kleijn H. 141 176 313 Klein A. J. 160 Klein J. 106 Klein M. G. 370 Klein R. S. 348 Klemer A. 357 Kleschick W.A. 202 326 Kleveland K. 11 1 Kliger D. S. 29 Klimetzek D. 369 378 Klink J. R. 237 Klinkmuller K.-D. 202 Klioze S. 424 Kluge A. F. 374 Klun J. A. 368 Klunkin G. 220 Knapps S. 280 Kneen G. 64,23 1 Knittel P. 189 Knozinger H. 124 193 Knoll F. 258 Knolle J. 366 Knothe L. 243 Knowles J. R. 432,437 Knowles W. S. 122 412 Knust E. J. 224 Knutson P. L. A. 137 Knyazev V. N. 227 KO E. C. F. 77 Kobayashi H. 21 Kobayashi K. 260,436 Kobayashi S.,365 Kobayashi T. 390 Kobayashi Y. 278 330 Kobrina L. S. 222 Koch T. H. 258 Kochansky J. P.,367 368 Kochetkov N. N. 347 Kochi J. K. 96 Kochloefl K. 124 193 Kocienski P. J. 381 383 386. 387,389 Koczorowski G.433 Kodama H. 146 Kodama M. 92 Koeberg-Telder A. 225 Koebernick H. 363 Koebernick W. 363 Ko11 P. 353 Kolle O. 262 Koppel C. 8 Koetzle T. F. 12 Koge M. 225 Kogure T. 121,205 Kohler B. E. 27,28,30,31,32 Koizumi M. 10 Kojo S. 416 Koka P. 23 32 Koll A. 227 Kollman P. 57 58 Kollrnar H. 241 Kolotilo N. V. 278 Komae H. 372 Komamura T. 112 Komatsu K. 63,241,245 Kornornicki A. 241 298 Komura H. 345 Kondo K. 63 275 288 312 391 Kondrat R.W. 10 Kongkathip B.,388 Konishi H.. 241 Author Index Konno Y.,275 Konoike T. 330 Kopf J. 361 Koptyug V. A. 225 237 Kornblum N. 322 Korner M. 443 Kornuta P. P. 278 Korytnyk W. 359 Korzeniowski S. H. 229 376 Kosbahn W.277 Koschatsky K. H. 383 Koshy K. M. 189 Kossanyi J. 168 388 Kosugi M. 151 Kovner M. 28 Kowalski J. 192 Koyama K. 108 Krajcarski D. T. 420 Kramer R. 313 Krantz A. 174 253,257 434 Krapcho A. P. 323 Kraus G. 288 Kraus G. A. 320 Kraus J. L. 433 Kraus M. A. 139 Krause J. G. 265 Krauss D. 375 Krautler B. 423 Krawczyk Z. 197 Krepski L. R. 185 Kresge C. T. 299 Krestonosich S. 220 Kretschmer G. 258 Kreysig D. 237 Krief A. 212 Krieger C. 235 Kriegesmann R. 312 Kriemler H.-P. 427 Krishnamurthy S. 143 320 Krolikiewicz K. 336 Kropp P. J. 167 Kroto H. W. 149 Krueger D. S. 326 332 Kruger A. 163 Kruger T L. 8 10 Kruglyak Y. A. 47 Krull I.S. 378 Kruse C. 277 Kruse L. I. 285 340 Krusell W. C. 135 Krusic P. J. 96 Kryger R. G. 222 Krysin A. P. 237 Ksander G. M. 327 Ku A. 61 170 Kubo I. 377 Kubota T. 377 Kucherov V. F. 327 Kudo Y.,273 Kueh J. S. H. 342 Kuepper F. W. 386 Kiisefoglu S. H. 233 Kugelman M. 365 Kuhla D. E. 282 Author Index Kuhn H. 25 Kukla M. J. 216 293 Kulakowska I. 14 Kulkarni S. U. 190 Kumada M. 126 148,229 Kumadaki I. 278 Kumagae K. 233 Kumakura M. 369 Kuper D. G. 110 Kupperman A. 29 Kurihara M. 368 Kurita J. 279 Kuroda K. 168 Kuroda S. 244 Kurtin W. E. 34 38 Kurzawa J. 83 Kuster T. 9 Kuwahara Y. 371 386 Kuwajima I. 203 209 260 326,327,333 Kuznetsov S.G. 177 Kvarnstrom I. 345 Kventsel G. V. 26 Kwiatkowski J. S. 38 Kyba E. P. 116 117 Laarhoven W. H. 174,240 Labaw C. S. 265 L'abbC G. 256,257 Laberge S. P. 38 Labhart H. 37 Labovitz J. N. 367 368 Ladd T. L. 370 Lammerzahl F. 138 Lagier R. F. 368 La Grange J. 58 Lai C. C. 265 Laidler D. A. 281 356 Laing G. 78 Lake D. H. 221 Lakwijk A. C. 379 Lal B. 202 Lalanne-Cassou B. 383 La Mattina J. L. 277 332 Lambert G. 103 Lambert J. B. 3 272 Lambert R. L. jun. 149 Lam-Chi Q. 365 Lamm B. 161 Lampin J. P. 3 11 Landells R. G. M. 98 Landman D. 7,245 Landor P. D. 182,184,317 Landor S. 118 Landor S. R. 182 184,317 Lane G. A. 296 Lane M. D. 440 Lang E. 295 Lang G.431 Lange B. 199,263 Lange B. C. 137,325 Lange G. L. 166 Langs D. A. 16 Lanier G. N. 372 Larcheveque M.,203 Lardicci L. 126 Larock R. C. 175,229 Latham D. W. S. 264 Lattes A. 133 185 Lau P. W. K. 187 Laube B. L. 154 Laue H. A. H. 92,96 Launer C. R. 300 Laura R. 433 Lauransan J. 270 Laurenco C. 314 Laureni J. 174 253 Laurie V. W. 297 Laval J.-P. 133 185 Lavallee P. 366 Lavrik P. B. 216 Law K. Y. 167 Lawrence L. A. 368 Leardini R. 264 Leary G. 230 Leaver D. 245,260 le Bot Y. 276 Le Breton P. 85 Lechleiter J. C. 166 Ledford N. D. 295 Ledlie D. B. 78 241 295 Le Drian C. 336 Lee C. B. 183 Lee C. C. 74,77 Lee E. 424,425 Lee H. J. 437 438 Lee H.M. 63 Lee S. J. 303 Lee S. L. 424 Lee T. S. 231 Lee Y. W. 377 Leenstra W. R. 21 Leffek K. T. 83,227 Lefferts J. L. 149 Lefour J. M. 60 190 Legrand Y. 208 Le Guillanton G. 77 Lehman T. A. 3 Lehmann H. 243 Lehr F. 200 Leight R. S. 69 307 Leiserowitz L. 12 Lelli M. 264 Lemal D. M. 255 Lemieux R. U. 343,344 Lenoir D. 185 Lentz C. M. 138,340 Leonard J. J. 19 Upine M.-C. 363 Leroux J. 346 Leroy G. 58,59 Lessinger L. 12 Lester D. J. 325 Lester R. 368 Leung H. W. 228 Leung T. 144 Leung Y.-K. 189 459 Levi A. J. 440 Levinson A. R. 370 Levinson H. Z. 370 376 Levit A. F.,98 Levitt L. S.,87 Levitt T. E. 205 Levkoeva E. I. 282 Levsen K.3,4,5 6 8 Levy A. B. 176 319 Levy E.S. 399 Lewars E. 253 Lewellyn M. 166 186 292 312 Lewis N. J. 223 Lewis T. 379 Lewis T. P. 38 Lex J. 63 249 Ley S. V. 127 216 229 293 325 335 Leznoff C. C. 213 310 380 384 Liaaen-Jensen S. 32 Liang G. 241 243 246 300 Lias S. G. 7 Libman N. M. 177 Liebelt W. 124 193 Liebl R. 277 Liebman J. F. 285 Lieder C. A. 87 Liepa A. J. 238 Liles D. C. 150 Lilienblum W. 111 Liljenberg C. 419 Lim T. F. O. 147 148 Limbach H.-H. 243 Lin C.-T. 14 Lin J. J. 141 309 Lindahl K. 372 Lindberg B. 356 Linden H. W. 269 Lindley J. M. 109 Lindley N. B. 296 Lindley P. F. 270 Lindner H. J. 62 265 Lindsay D. 180 Lines R. 162 Ling A.C. 101 Link H. 255 Linke S. 108 Linstrumelle G. 141 384 Liotta D. 207 332 Liotta R. 190 Lipkowitz G. S. 434 Lipkowitz K. B. 282 Lippert B. 436,437 Lipscomb W. N. 54 Liptik A. 358 Lipton M. S. 307 Lissel M. 110 Little W. 322 Litton J. F. 8 10 Litwack G. 440 Liu J. C. 258 Liu L.-K. 168 239 Llambias E. B. C.. 396 Llort F. M. 137 Lloyd H. A. 372 Loc c.v. 10 Lochmann R. 56 Lochmueller H. 441 Lockridge O. 433 Liinngren J. 356 Lofquist J. 372 374 Logan D. M. 379 Lohmann J.-J. 113 267 Lohse C. 174 273 Lombardino J. G. 282 Longo F. R. 19 Longone D. T. 233 Loof I. H. 114 Loots M. J. 177 313 Lorand J. P. 222 Lorenc J. F. 266 267 Lorne R.141 Loskant G. 369,378 Lotts K. D. 285 Loubinoux B. 179 Loudon A. G. 4 Louterman-Leloup G. 58 Lovas F. J. 256 Lo Vecchio G. 264 Lovey A. J. 323 Loza R. 113 Lu S. H. 423 Luanglath K. 107 Lubineau A. 350 Lubosch W. 136,336 Lucchese R. R. 110 Lucchini V. 179 253 Luche J.-L. 181 Ludwig M. L. 39 Luddecke E. 267 Ludemann H.-D. 295 Luger P. 270 LuklE J. 255 Lukefahr M. J. 190 377 Lumsden J. 444 Lunazzi L. 98 Lund H. 158,159 Lusby W. R. 371 Luteri G. F. 61 Luthy J. 410 Lutz M. 19 Lutz W. 327 Lwowski W. 108 Ly N. D. 260 Lyda M. 95 Lyle R. E. 276 Lynch B. M. 217 Lynd R. A. 317 Lynen. F. 441 Lysenko Z. 206,335 Lyster M. A. 202 320,332 Lythgoe B.65 312 Lyznicki E. P. 189 8 Maarsen P. K. 226 Mabry T. J. 377 McAdoo D. J. 9 McAlister 3. R. 220 Macaluso,D 268 Macauley E'D. M. 379 MacBride J. A. H. 274 McBride J. M. 110 McCaffery L. K. 21 Maccagnani G. 269 McCandless L. L. jun. 379 McCapra F. 169 193 McCaskie J. E. 258 McClain W. M. 29 McClelland R. A. 77 McCloskey C. J. 341 McCombie S. W. 312 349 361 MacConnell J. G. 374 McConwick J. 11 McCullough J. J. 64 231 McCurry P. M. jun. 289 McDaniel C. R. jun. 295 MacDiarmid A. G. 163 McDonach A. F. 400 McDonald E. 393 396 397 398,399,401,402,404,405 407,411,413,417,424,425 427 McDonald F. J. 374 MacDonald L. M. 379 McDonald R. N. 162 MacDonald S.F. 398,420 MacDonell G. D. 282 McDonough L. M. 369 McDowell P. 390 McEwen F. L. 376 McGarvey G. 319 McGinnis J. 132 185 303 McGovern W. L. 370 McGuirk P. R. 313 Machiguchi T. 242 299 McHugh A. J. 19 McIver R. T. jun. 85 140 202,216 Mackay D. 269 Mackay G. I. 87 McKean D. R. 318 McKee M. L. 65 145 McKelvey J. H. jun. 367 McKervey M. A. 302 McKibben G. H. 370 McKillop A. 147,222,229 McKinnie B. G. 139 Mackinnon J. W. M. 109 McLafferty F. W. 5,7. P 9 10 McLaren F. R. 112 341 McLaughlan K. A. 104' McLaughlin J. L. 10 McLean J. A. 372 McLennan D. J. 82,83 McMahon T B. 85 McManus S?P. 47,75 McMaster I. T. 108 109 McMeeking J. 301 McMurray J. E. 185,327,336 341 Author Index McOmie J.F. W. 241 McOsker C. C. 188,313 McPhail A. T. 366 MacPhee J. A. 206 McQuilkin R. M. 378 McQuillan F. J. 192 McRobbie I. M. 109 Madan P. B. 265 Madawinata K. 199 Madhavarao M. 129 Madsen H. 368 Markl G. 277 278 Marky M. 172 Magee W. L. 113 Maggiora G. M. 19 20 Magnus P. 149 324,331,387 Magnusson G. 383 Mah H. D. 398 Mahaffy P. G. 231 Maier G. 242 257 274 299 Main P. 11 12 Maisey R. F. 236 Maister S. G. 437 Maitlis P. M. 123 Mak N. 10 Maki Y. 142,257 319 Makinen M. W. 39 431 Makino T. 16 Malek F. 180 309 Malek J. 339 Malkiewich C. D. 227 Malkowski J. 270 Mallams A. K. 365 Mallik B. 30 Mallon C. B. 11 1 Malpass J.R. 107 Mamatyuk V. I. 225 Mammarella R. E. 151 312 Mandai T. 189 Mandal A. K. 190 Mandal K. 30 Mandell L. 324 Mander L. N. 399 Mandolini L. 205 Mangner T. J. 9 Mango F. G. 133 Mangum M. G. 118 Manhas M. S. 202 252 Manisse N. 254 Mrnn C. K. 154 Mg!hing C. 64 220 231 Mgnning M. J. 232 Mh? 1). M. 11 Mhtuh W. W. 23 MaqueRiau A. 4,7 Marchon T.-C. 431 Marcinal P. 234 Marcotte P. 433 Marfat A. 313 Margoliash E. 396 Margolis H. 261 Margolis Z. 86 Mariano P. S. 171 276 Marino G. 282 Marino J. P. 289 Author Index Mark F. 60 Mark H.B. jun. 163 Markiewicz W. 207 Markovac A. 420 Markovetz A. J. 378 Markovskii L. N. 278 Markowski V. 69,253 Markwell R.E. 402 Marquet A. 438 Marrero R. 332 Marschall H. 202 Marsden J. R. 118 Marshall J. A. 166 186 292 312 Marshall J. H. 163 Marshall J. L. 262,276,295 Marshall P. D. R.,95 Marten D. F. 129 Martigny P. 161 Martin G. J. 208 Martin H.-D., 290 Martin J. C. 261 Martin K. O. 437 Martin M. D. 390 Martin M. J. 382 Martin M. L. 208 Martin R. H.,240 241 Martin S. F. 195 327 Martha D. 62 Martineau A. 105 Martinez R. I. 256 Martyr R. J. 439 Marumo S. 378 Maruoka K. 207 Maruthamuthu P. 99 Maruyama K. 61,313 Maryanoff C. A. 277 Marziano N. C. 224 Masaka K. 189 Masaki M. 107 Masamune S. 242 246 252 290,299,336 Masamune T. 317,330 Masaoka K. 380 Mashenkov V.A. 21 Masilamani D. 192 Massardo P. 368 Massey V. 433 434 Massot R. 3 Massuda D. 117 Masters C. J. 446 Masuda S. 217 Masumoto K. 241 Matchett W. H. 443 Math V. B. 25 Matheson J. H. 396 Mathewson J. H. 406 Mathey F.. 3 11 Mathis F. 271 Matinopoulos-Scordou A. E. 227 Matjeka E. R. 232 260 Matlin S. A. 105 407 Matsen F. A. 299 Matsuda K. 350 Matsue H. 317 Matsui K. 231 Matsui M. 347,354,360,366 386,390 Matsumoto K.,154 Matsumoto M. 63 168 250 391 Matsumura F. 370 371 377 Matsumura H. 244 Matsumura T. 93 Matsumura Y. 153 323 Matsuno A. 345 Matsuo M. 200 Matsushima R. 358 Matsuura T. 230 231 Mattay J. 171 220 Matteoli U. 122 Matthews W.G. 86 Maurin R. 184 Maycock A. L. 432,433,434 Mayr H. 80 Mazenod F. 218 302 Mazid R. M. 318 Mazur Y. 200 324 Mazza F. 13 Mazzanti G. 269 Medimagh M. S. 69 Meegan M. J. 405 Meesters A. C. M. 199 Meguro S. 124 Meier H.,63 112 115 198 279,282 Meijer J. 141 149 176 313 Meiler V. W. 49 Meinwald J. 261 280 367 374,375 Meissner U. E. 248 Meister J. 180 Melchior M. T. 223 Melega W. P. 149 187 246 300,312 Mellon F. A. 372 Mellor J. M. 156 281 Mellor M. 342 Mel’nikov G. D. 177 Mel’nikov N. N. 282 Mel’nikov S.P. 177 Menchen S. M. 312 Mendelowitz P. C. 149 Mendelsohn R. 33 Menke K. 233,234 Menzer R. E. 371 Menzies W. B. 245 260 Merenyi R. 254 Meritt M.V. 102 Merrifield D. L. 295 Merz A. 159 Messer L. A. 181 Mestroni G. 123 Metcalf B. W. 436 437,443 Metcalfe D. A. 65 Metcalfe J. 110 Meth-Cohn O. 109 264 Metzger J. 270 Meyer. H. H. 388 461 Meyer L.-U. 305 Meyer M. D. 181 Meyer R. 199 Meyer T. J. 163 Meyer V. 168 Michalski J. 210 Michel D. 49 Michelot D. 384 Michl J. 231 Middleton E. J. 390 Middleton R.,174 Midelfort C. F. 437 Midland M. M. 143 181 317 Migake Y. 433 Migita T. 15 1 Miki Y. 275 Milat M.-L. 345 Mildvan A. S. 442 Millard A. A. 335 Millen P. W. 270 Miller B. 141 232 260 Miller D. C. 355 361 Miller I. J. 230 Miller J. M. 204 244 339 Miller J. R. 377 379 Miller J.S. 85 Miller R.B. 319 Miller R. W. 370 371 Millington D. S. 408 Mills J. A. 343 Milun M. 215 Mimura T. 327 Minami N. 209,333 Minato T. 64 Minks A. K. 367,368 369 Minot C. 60 190 Minov V. M. 227 Minter D. E. 307 Mioskowski C. 212 Mirbach M. F. 171 220 Mirbach M. J. 171 220 Mirek J. 221 Miser J. R.,223 Mislow K. 137 150 277 Misra R. N. 149 319 Misra T. N. 30 Misumi S.,13 233 235 250 Mitchell E. B. 370 Mitchell R. H. 238 Mitchell T. R. B. 302 Mitsuhashi T. 238 Miura I. 377 Miura Y. 233 241 Miura Z. 375,377 Miyashita D. 376 Miyaura N. 335 Miyazawa S. 436 Miyoshi M. 154 Miyoshi N. 189 Mizoroki T. 124 Mizumachi N. 390 Mizuno H. 13 Mizuta M. 209 Mizutani J.371 Mo F. 13 Mock W. L. 63 Modena G. 178,179,253 Modro A. 84 178 Mody N. V. 387 Moffatt J. G. 348 354 Mol J. C. 133 185 Molander G. A. 143 Molnar A. 278 Mombelli L. 401 Monaghan F. 240 Monder C. 437,438 Monneret C. 359,362 Monroe R. E. 378 Monstrey J. 6 Montevecchi P. C. 112 253 Montforts F.-P. 397 Montgomery L. K. 231 Montgomery M. E. 373 Monti S. A. 293 Montoya A. L. 444 Moodie R. B. 224 Moore B. P. 371 Moore,T. A. 22,28,30,32,33 38,39 Morales O. 63 Mordenti L. 179 Moreau-Hochu M. F. 105 Moretti I. 197 Morey K. S. 440 Morgan E. D. 372,379 Mori K. 369 372 378 379 380,381,382,386,389,390 Morimoto N. 13 Morin C. 282 Morin F.G. 296 Morio K. 290 Morita T. 245 Morizur J.-P. 168 388 Morokuma K. 44 51,54,57 Moron J. 396,399 . Morris H. R. 417 427 Morrison A. 32 Morrison G. 253 Morrison H. A, 173 Morse C. S. 225 Morton J. 366 Morton T. C. 420 Moses P. R. 157 Moses V. 446 Mosher 0.A. 29 Mosher H. S. 121 Moss G. P. 419 Moss J. 440 Moss R.A. 111,200 Mostowicz D. 197 Mott R. C. 326 Mount D. L. 75 Moutsokapas A. A, 113 Mowbray J. 446 Mpango G. M. 184 Muchowski J. M. 331 Miillen K. 249 Miiller G. 398 404,424 427 Mues P. 249 Muetterties E. L. 123 134 135 Muhs W. H. 360 Mukaiyama T. 203 251 318 326,381 Mulder F. 46 Mulder J. J. C. 218 Muller P. 114 Muller P. M. 423 Mullins M.J. 280 Mulzer J. 312 Munasinghe V. R.N. 362,364 Munavu R. M. 354 Mundy P. P. 282 Munoz A. 271 Munroe J. E. 48 Murahashi S.-I. 110,143,189 309,313,338 Murai A. 317 330 Murai S. 127 142 189 289 312 .bfli;akami M. 100 X~;irL.noto H. 368 Murase H. 317 Murata,m, 245 Muram N. 108 Murawski H.-R., 64 Murayama K. 143 Murphy M. J. 426 Murphy W. S. 62 Murray R.E. 317 Murrell J. N. 149 Mutin R. 133 185 304 Mychajlowskij W. 187 385 Myhre P. C. 225 Nabbefeld E. F. 126 Nader F. 12 Naf F. 384 Nagai S. I. 273 Nagasawa J. 364 Nagata C. 92 Naiman A, 126 Nair K. S. S. 376 Nakadaira. Y.,148 257 Nakagawa K.-I. 148 Nakagawa M. 246 247 249 291 Nakagawa Y.,108 Nakai T.327 Nakajima H. 368 Nakamura. C. Y.,325 Nakamura E. 203,326 Nakamura K. 195,230 Nakamura N. 386 Nakamura R. 133 Nakanishi K. 375 377 Nakatsuji S. 247 249 Nakayama J. 232 Nakazaki M. 165,233 Nakazawa T. 245 Nakazima Y. 342 Author Index Ninisi 9..358 Nandi D. L. 394 Nash A. 374 Nassr M. 345 Natarajan S. 317,387 Nau H. 3 Nault L. R. 3/73 Nay B. 107 Neckers D. C. 172 219 Negishi A. 63 Negishi E.-I. 132 136 141 142,143,175,176,229,282 313,316,317,382,384 Neidert E. 166 Neidle S. 17 Neill D. C. 174 197 Nelander B. 262 Nelsen. S. F. 163 Nelson D. J. 103 Nervi A. M. 440 Nesbitt B. F. 368 iue-jitt S. L. 325 Nester E. W. 444 Nesbittilyi A.358 Nesbittchwander M. 243 Newcomb M. 69,204 Newkome G. R. 274,282 Newman M. S. 238 Newton J. R.,379 Newton M. D. 52 Newton P. F. 296 Newton R.F. 168 341 Nibbering N. M. M. 6 7 8 273 Nicolaou K. C. 206 335 336 Nicoletti R. 196 Nie P. L. 252 Nielsen J. U. R. 4 Nielson M. W. 373 Niki E. 102 Ning R. Y.,265 Nishida R. 371 386 Nishiguchi I. 112 Nishiguchi K. 13 Nishikawa Y.,275 Nishikida K. 100 Nishimoto K. 19 38 Nishinaga A. 230 231 Nishino C. 371 373 378 Nishio T. 108 Nishishita T. 5 8 10 Nishiyama K. 109 Nishizawa K. 231 Nishizawa M. 320 Nixon L. N. 398 Noall W. I. 189 Nocci R.,126 Noding S. A. 146 Noe E. A, 205 Noell J. O. 44 Noth H.143 Noltes J. G. 177 229 Nomoto T. 247 Nonhebel D. C. 222 Author Index Nooijen P. J. F. 371 Nooijen W. J. 367 368 371 Nord L. 262 Norden B. 20 Nordman C. E. 16 Norman R. 0. C. 91 92 95 96,97,100,101,274 Normant J. F. 131 140 141 314,319 Norris D. M. 379 Norris J. R. 23,429 Norris T. 270 Northrop D. B. 441 Noto R. 228 Nov E. 236 Novi M. 240 Novoselov N. P. 45 Nowak R. J. 163 Nowlan,V. J. 84,184,189,248 Nowotnik D. P. 265 Noyori R. 203,326 Nozaki,H. 112 149,176,188 207,342,384 Numan H. 169,258 Nunokawa 0..327 Nutakul W. 221 Nyburg S. C. 75 Oae. S. 108 282 Oakley R. T. 278 Obayashi M. 149 176 384 Oberhansli W. E. 255 O’Brien D. H. 190 377 O’Brien E.220 O’Carra P. 429 Ochoa M. 161 O’Connell E. L. 437,442 O’Connor J. G. 235 OConnor J. P. 135 Oda. M. 246 Oda N. 273 Odier L. 353 Odyek O. 182 317 Oehling H. 100 Oei A. T. T. 94 Oei H.-A. 174 Oertle K. 336 Oettmeier W. 429 Offenhartz B. H. 24 Offenhartz P. O. 24 Ogata H. 433 Ogata I. 119 Ogata Y. 237 Ogawa S. 280 Ogawa T. 347,354,360,366 Oh S. W. 437 O’Hanlon P.. 408 Ohfune Y. 335 Ohloff G. 384 Ohnishi Y. 194 Ohno A. 195 Ohno T. 142 Orht J. M. 17 Ohsawa A. 273 Ohta K. 368 Ohta T. 229 Ohto N. 102 Oikawa H. 246 Ojima I. 121. 205 Ojima J. 248 Oka S. 195 Okamoto H. 257 Okamoto K. 63 241 245 Okamoto T. 229 Okano M.179 189 qkazaki H. 179 Oki M. 238 Okinoshima H. 148 Okude Y. 112 Okukado N. 141 175 229 317 Okumura K. 110 Olagbemiro T. 374 Olah G. 7 78 80 81 181 185,189,202,241,243,246 298,299,300,323,324,332 OlivC S. 119 126 185 Oliver J. P. 137 Olivers W. L. 272 Ollis W. D. 66 270 Olmstead W. N. 87 Olofson R. A. 196 285 Omoto H. 153 Onan K. D. 366 O’Neill P. 96 Ono M. 330 Ono Y. 92,93 Onoe A. 179 Onyido I. 228 Operaeche N. N. 364 Opperdoes F. R. 446 Oppolzer W. 285 Orere D. M. 338 Orger B. H. 171 Orly J. 443 Ornstein P. L. 202 318 325 Orr A. F. 336 Ors J. A. 220 Osawa E. 302 Osawa Y. 16 Osborn M. E. 276 Oscarson S. 354 Oschmann W. 262 OseIla D.135 Osgerby J. M. 398 O’Shea D. C. 22 Oshima K. 365 Osman F. H. 272 Ostlund N. S. 297 Ostrow R. W. 381,387 Osuka M. 247,249 Ota K. 240 Otani S. 142 Oth J. F. M. 249 Othen D. G. 150 Otsubo T. 13 233 234 235 250 Otsuji Y. 110 Otsuka S. 238 Ovchinnikov A. 26 Overend W.G. 353 Overman L. E. 140 Owicki J. C. 43 Oyama K. 189 Ozaki A. 124 Packard B. S. 272 Paddock N. L. 278 Paddon-Row M. N. 243,258 Padwa A. 61 113 166 167 170 Page A. D. 263 Pahor B. 220 Paige J. N. 63 Paik H. N. 129 243 Paine A. J. 77 Paine J. B. 111 407 Painter A. 347 Palakis S. E. 440 Palensky F. J. 173 Pancoast T. A. 212,386 Pandit U. K. 194 Panfil I. 197 Papadopoulos E.P. 252 265 Paquette L. A. 61 116 149 187,215,216,219,246,293 294,299,300,312 Parfitt R. T. 265 Parkanyi L. 277 Parker D. G. 181 Parker D. H. 29 Parker V. D. 162 Parkes D. A. 101 Parkhurst L. J. 32 Parlman R. M. 128. 330 Parr W. J. E. 295 Parriot P. 140 Parrish F. W. 343 Parrott M. J. 99 Parthasarathy R. 16 17 Partridge C. W. H. 444 Paschal J. W. 295 Passannanti S. 391 Passerini R. 224 Patchornik A. 139 Patel R. C. 272 Patin H. 124 Patnaik P. 123 Paton R. M. 98 101 Patrick T. B. 118 Pattenden G. 334 336 342 Paul I. C. 14 15 Paulsen H.,344,353,355,361 363 Paulus H. 383 Pavlik J. W. 173 Pawlak M. 384 Payne T. L. 378 Payzant J. D. 85 87 Peacock J.W. 372 464 Author Index Peawck R. D. 20 Pearce A. 186 Pearce G. T. 372,379,389 Pecul. K. 54 Pedder D. J. 374 Pedersen E. B. 137 Peel J. B.. 217 Pellacani L. 109 Pelletier. S. W. 387 Pellicciari R. 287 Pelter A. 144 205 268 Peng C. 137 Penney M. R. 269 Pepe J. P. 196 Perahia D. 49 Percy J. E. 367 378 Perevalov V. P. 261 Pereyre J. 165 Perham R. N. 445 Periasamy M. P. 298 Peries R. 140 Perkins M. J. 102 Perlin A. S. 346 Perrin C. L. 224 Perry N. 74 Perry R. A. 334 Persico M. 68 Persin M. 163 Person H. 107 Persoons C. J. 367 368 371 Perutz M. F. 431 Pete J.-P. 362 Peters E. N. 71 81 Peters K.S. 256 300 Peterson M. 28 Petke 3.D. 19 Petrocire D. 425 Petrov A. A. 178 Pettei M. J. 377 Pettersen R. C. 276 Pettit R. 323 Pettit W. A. 64 231 Petty J. D. 137 Petty R. L. 367 Pfaltz A. 423 Phadungkul N. 276 Philips J. C. 63 Piacenti F. 122 Piancatelli G. 259 Picavet J. P. 271 Piccardi P. 368 Picker K.,213 Pickholtz Y.,125 Pickworth J. 423 Pienta N. J. 167 Pierce B. M.,30 Piers E. 339 Pieter. R. 195 Pietra F. 243 Pikulik I. 215 290 Pilati T. 12 249 253 Pilkiewicz F. G. 375 377 Pilotti A. M. 280 Pinchuk V. M. 47,52 Pinwck J. A. 113 297 Pine S. H. 236 Pinet M. 105 Pinnick H. W. 285 Pitman G. B. 372 378 Pittman C. U. jun. 135 323 Placucci G. 98 Platz H. 369 Plaumann D. E. 363 Plieninger H.430 Pliske T. E. 369 Plomp R.,258 Plummer E. L. 379 Plummer E. W. 193 Plus R. 19 Pluscec J. 398 Podslawczynska,I. 213.321 Poehlmann; H. 260 Poels E. K. 266 Pohmakotr M. 139,205 Poindexter G. S. 167 Poirier J.-M. 140 Pojer P. M. 343 Polglase W. J. 41 1 Pollack S. K. 216 Pommer H. 184,310 Pommier J.-C. 196 Pomonis J. G. 377 Pong R. G. S. 174 Ponticelli F.,263 Poor R. W. 19 Popa V. 137 Pople J. A. 53 136 140 177 Popjlk G. 413,419 Poppinger D. 63 140 177 Portella C. 362 Porter N. A. 60 Posner G. H. 138,319,340 Post D. E. 29 Poto E. M. 441 Potter G. J. 189 Potts K.T. 262 Pougny J.-R.,345 Poulain E. 55 Poulson R. 411 Poulter C. D.186,203,313 Power M. J. 348 Prakash G. K.S. 185,243,324 Pramanik B. N. 202 Preiner G.. 147 Preston P. N. 270 Prestwich G. D.. 375 Pretzer W. R. 135 Prickett J. E. 109 Priesner E. 369 Priester W. 177 Primeau J. L. 365 Prinstein R. M. 5 Prinzbach H. 70 218 243 244,279 Pritt J. R. 75 Proidakov A. G. 180 Prokseh E. 323 Prosen R. J. 423 Pross A. 217 Protschuk G. 287 Proveaux A. T. 370 Proverbs M. D. 379 Pryor W. A. 222 Puckett S. A. 14 Pullman A. 41 47 49 50 Pullman B.. 13 38,49 50 Purdham J. T. 374 Purdum W. R. 282 Quagliata C. 13 Quast H. 256 276 Quinkert G. 314 Quinn C. P. 101 Rabek J. F.,90 Rabideau P. W. 295 297 Rabiller C. 208 Rabinovich D. 14 Rabinovitz M.216 246 247 249 Radchenko S. I. 178 Radmer R. 396 Radom L. 7 Rae I. D. 216 Raghavan R. S. 110 Rahimi P. M. 248 Rajan S. 227 Rakowski M. C. 123 Ralph L. M. 238 Ramaiah M. 331 Raman K. P.,62 Rampal J. B. 277 278 Rampazzo L. 159 Ramsden C. A. 252,270,272 282 Ramsey B. G. 144 Ramunni G. 59 RAnby B. 90 Randii M. 215 Rando R. R. 432,433,436 Ranieri R. L. 10 Rao B. L. 359 Rao C. G. 71 Rao Y.S. 282 Raoult E. 162 Rapoport H. 403,416 Rapp K.M. 245 Rapp U. 8 Rappoport Z. 75 77,78 Rasheed K. 280 Rasmussen J. K. 325 Raston. C. L. 152 Rathbone E. B. 362,364 Rathke M. W. 335 Ratovelomanana V. 117 Radom L. 63 Rau H. 267 Raucher. S.318 Rauchschwalbe R. 295 Author Index Rauscher S. 368 379 Ravid U.,390 Ravindran N. 142 Ravindranathan M. 71 72 Ravindranathan T. 68,293 Rawlins M. F. 281 Rayez J. C. 49 Raynolds P. W. 232 Read D. M. 272 Read J. S. 368 Reasoner J. W. 92 Reddy G. S.,7 Redfern J. R. 397,411 Redmond J. W. 410 Reed C. A. 431 Reed L. E. 114 Reed L. J. 443,445 Rees J. H. 224 Reese C. B. 338 355 Reetz M. T.. 67 83 149 Regel E. 264 265 Regen S. L. 110 Reich H. J. 21 1 Reichert 0.M. 141 Reichle R. 74 Reichrnanis E. 276 Reifz T. J. 386 Reil S. 403 Reinehr D. 126 Reinhoudt D. N. 282 Reissenweber G. 279 Reissig. W. H. 369 Reiter S. E. 245 260 Reitz D. B. 139 Reitz T.J. 212 Renga J. M. 280 Renger B. 136 195 336 Rennecke R.-W. 353 Renner C. A. 308 Renwick J. A. A. 372 378 Renz P. 423 RCtey J. 410 Reuter J. M. 328 Reutrakul V. 327 Reynolds W. F. 151 216 Rezende M. C. 196,252,334 Rho M. M. 71 Rhyne L. D. 241 Rice S. A. 27 Rich A. 38 Richards K. E. 225 Richardson A. C. 355 Richmond G. 6 Richon A. B. 390 Ricker A. 279 Ridd J. H. 224 Ridley D. D. 320 332 Rieke R. D. 137,158,241 Riemann J. M. 222 274 Riepertinger C. 441 Riganti V. 60 Righetti P. P. 60 Rimmer J. 419 Rinehart K. L. jun. 365 Ring H. 127 Ripoll J. L. 181 Ris C. 225 Risch N. 423 Risitano F. 264 Rist G. 290 Ritchie. C. D. 217 Ritter F. J.367,368,371,373 Rivetti F. 178 Robacker D. C. 373 Robbiani R. 9 Roberts B. P. 97,99 100 Roberts B. W. 128 Roberts J. D. 87 Roberts J. L. 186 203 313 Roberts P. 302 Roberts S. M. 168 341 Roberts T. D. 112,253 Robertson A. J. B. 102 Robertson J. H. 423 Robertson T. H. 127 Robey M. J. 36 Robins M. J. 360 Robins R. K. 37 Robinson C. H. 433 Robinson J. A. 427 Robinson W. T. 43 1 Roderneyer G. 357 Roden K. 363 Rodewald H. 235 Rodionov V. Ya. 261 Rodriquez O. 170 Roelofs W. L. 367 368 369 377,378,379 Rogers V. 118 RogiC M. M. 192 Roloff A. 126 Rommel E. 168 Rona R. J. 149 Ronchi N. 98 Roomi M. W. 420 Rooney J. J. 119 302 Roos B. O. 110 Roper J. M. 282 Rose I.A. 410 437 442 Rosenblum L. D. 386 Rosenblum M. 129 Rosenstock H. M. 3 Rosenthal D. 426 Rosini G. 264 Rosmus P. 268 Ross I. G. 36 Ross J. A. 255 Ross K. H. 256 Rossa L. 233 Rossi M. 123 Rossi R. 380 384 386 Ross-Mansell P. 440 Roth M. D. 110 Rothenberg S. 57 Rothermel W. 262 Rothschild A. J. 114 Roussel C. 270 Roussi. G. 189 Roustan J. L. 182 Rowe M. D. 21 Rozental J. M. 379 Rozhkov I. N. 153 Ruasse M.-F. 84 177 Rubottom G. M. 326,332 Ruchiwarat S. 276 Ruder J.-P. 243 Riichardt C. 69 180 Ruge B. 238 Ruggeri M. V. 258 Rundle J. W. 85 Runquist A. W. 319 Runzheimer H.-V. 63,249 Russell M. J. 123 Russell R. A. 231 Russell-King J. 74 Russiello A.B. 265 Rutledge P. S. 189 Ryan R. C. 135 Rycroft D. S. 109 Ryder D. J. 401 Rylatt D. B. 440 Ryu I. 142 Rzepa H. S. 7 65 68 Sabacky M. J. 122,412 Saegusa T. 260 330 Saenger W. 14 Said I. M. 235 Saiki K. 273 Sainsbury M. 155 St. John G. A. 10 Saito I. 60 244 378 Saito M. 209 Saji T. 162 Sakaino M. 244 Sakan K. 244 Sakan T. 386 Sakata J. 203 326 Sakata Y. 250 Sakore T. D. 17 Sakurai H. 117,148,165,230 257,290,340 Salach J. L. 433 434 Salares V. R. 33 Salem L. 59 Salerno G. 125 Salmond W. G. 316 Salomon M. F. 150 302 Salomon. R. G. 150 169,302 328 Salzmann T. N. 380 Samain D. 383 Samberg G. 379 Samman N. G. 302 Sammes M. P.275 Sammes P. G. 272 Samori B. 20 Samuel C. J. 173 Sanchez M. 272 Sancovich H. A. 407 Sanders C. J. 368 Sanders J. K. M. 429 Sanders .M. E. 386 Sanechika K.-I. 245 Sannicolo F. 236 Sano H. 365 Sano S. 416 Santiesteban H. 207 332 Sargent F. P. 101 102 Sargeson A. M. 281 Sarhangi A. 324 Sarkar S. 123 Sarre 0.Z. 366 Sasaki N. 335 Sasaki T. 61 116 Sasaoka M. 253 Sato F. 146 Sato M. 146 244 Sato S. 146 Sato T. 157 327 371 386 Satoh F. 190 314 407 424 Satoh J. Y. 325 Saucy G. 202 207 Sauer J. D. 274,279,282 Sauer K. 23 Sauer W. 242,299 Saunders J. 396 397,407 Saus A. 171,220 Sauter H. 70 243 290 Saveant J. M.,161 Savoia D. 137 Sawada M.217 Sawada S.-I. 241 Sawyer D. T. 161 Scaiano J. C. 167 Scamehorn R. G. 227 Scarborough R. M. 207 Scarcelli N. 13 Scarpati R. 269 Scettri A. 259 Schaad L. J. 246 Schaap A. P. 258 Schaefer C. G. 386 Schafer H. 277 Schaefer H. F.,7 58 110 Schafer L. 295,297 Schafer P. 256 Schaefer T. 295 Schafer U. 257 Schaffer A. M. 31,32 Schallner O. 294 Scharf H.-D. 171,220 Schaumann E. 253 255 321 Schechter P. J. 436 Schechtman B. H. 20 Scheele J. J. 160 Scheer H. 429 Scheerer B. 201 Schegoler A. A. 327 Scheiner S. 53 54 Schenk W. N. 207 332 Schenkluhn H. 126 Scheraga H. A. 36,43 Scherowsky G. 269 Schickaneder H. 266 Schiess P. 222 Schiff H. I. 85 Schildknecht H.373,375 Schlecker R. 139 Schley B. 268 Schleyer P. von R. 71 116 140,177,302 Schlosser M. 260 Schmid G. 262 Schmid G. H. 84 178,282 Schmid H. 65 255 280 282 378 Schmid P. 102 228 236 Schmid R. 280 Schmidbaur H. 149 Schmidt D. E. 432 Schmidt D. J. 11 8 Schmidt R. R. 198 350 Schmidt S. P. 378 Schmidtchen F. 397 Schmieder K. R. 314 Schmitz H. 267 Schnarr G. W. 352 362 Schneider D. 367 Schneider D. F. 294 Schneider D. R. 69 Schneider H. P. 279 Schneider M. P. 305 Schnur R. C. 196 Schoeller W. W. 64 306 Schollkopf U. 137 199 Schonholzer P. 255 Schofield K. 224 Schonbrunn A, 433 Schonfelder W. 107 Schoppee C. W. 70 Schramrn M. 443 Schreimer K. 100 Schreiner J.L. 332 Schriener K. 298 Schroll G. 4 Schuchardt V. 301 Schuda P. F. 232 Schuerch C. 346 Schug R. 285 Schuh H. 101 Schulte G. 365 Schulte K.-W. 242 Schulte-Frohlinde D. 96 Schulten K. 27 30 Schulze J. 262 Schurvell H. F. 3 Schuster H. F. 258 Schuttler R. 114 Schwalm W. A. 94 Schwartz J. 131 134 146 177,313,322 Schwarz H. 3,4 5 8 Schweig A. 242 Schweizer E. E. 265 266 Scopes P. M. 25 Scordamaglia R. 43 Scorrano G. 178 Scott A, 322 Author Index Scott A. I. 399,409,424 425 Scott F. 382 Scott J. J. 398 Scott L. T. 239 Scrimin P. 179 253 Scriven E. F. V. 107 Scrocco E. 46 Scrutton M. 440 Sealy R. C. 104 Seebach D. 136 139 140 174,195,200,205,212,287 331,336 Segal G.59 Segden-Penne J. 311 Seguchi K. 61 Seibl J. 9 Seibold K. 37 Seidel K.D. 255 Seitz B. 112 Seki K. 124 Seki Y. 127 289 Sekiguchi A. 114 148 Sekiya A. 129 Sellers D. 379 Selva E. 60 Semrnelhack M. F. 64 130 307 Seo K. 361 Sepiol J. 221 Seppelt W. 244 Sera A. 61 Sergheraert S. 234 Sessions R. B. 281 Seto S. 350 Seufert A. 145 Sewing B. 136 212 336 Severin T. 200 260 Sevrin M. 212 Seyferth D. 148 149 150 151,312 Shaden G. 238 Shah S. K. 211 Shahak I. 106 Shakked Z. 14 Shamov A. G. 59 Shannon M. L. 148 Sharma D. K. S. 10 Sharma M. 359 Sharma R. A. 359 Sharma R. P. 109 Sharp D. W. A. 109 Sharp J.T. 98 Sharpless K. B. 192 320 365 Shaw J. 7 Shaw K. B. 420 Shaw T. J. 137,204 Shea K. J. 65 217 308 Shearer H. M. M. 150 Shechter H. 113,238 Sheikh H. 196 252 334 Sheldrick G. M. 15 Shelnutt J. A. 22 Shemin D. 394 Sheng S. J. 29 Author Index 467 Sheradsky T. 236 Shibanuma T. 25 1 Shibasaki M. 366 Shibuya T. 378 Shieh H. S. 16 Shih Y.-S. 230 Shimizu K. 342 Shimizu M. 203 326 Shimizu Y. 151 Shin H. J. 247 Shine H. J. 236 Shinmyozu T. 233 Shinoda M. 225 Shiono M. 251 Shipman L. L. 19 22 23 Shoda S.-I. 251 318 Shoer L. I. 134 146 Shono T. 112 153 323 Shorey H. H. 367 379 Shudo K. 229 Shvetsov-Shilovskii N. I. 282 Siebert W. 262 Siegbahn P.M. 110 Siegel B. 347 Siegel L. M. 426 Siegfried B. 223 Sierra J. R. 378 Silberglied R. E. 374 Silberman L. 340 Silvers J. H. 85 Silverstein R. M. 370 372 379,389,390 Sim S. K. 70 Simmons H. E. 300 Simon K. 126 Simonet J. 161 Simonetta M. 12,46,249,253 Simoni R. D. 29 Simons J. 45 Simpson G. W. 320 332 Simpson R. F. 378 Simpson W. T. 37 Sinay P. 345 Sinclair J. A. 143 Singer S. P. 280 Singer T. P. 433 434 Singh T. D. 273 Sinnewell V. 363 Siodmiak J. 39 Sjoerdsma A. 437 Sjoholm I. 440 Skattebol L. 11 1 112 382 Skell P. S. 289 Skelton B. W. 152 Sket B. 172 219 220 Sklar L. A. 28 29 Skrabal P. 270 Skrzypczynski,Z. 210 Slama J. T. 416 Slessor K.N. 372 Sliwa H. 271 273,274 276 Slobbe J. 153 Small L. E. 85 202 Small R. D. 167 Smallwood J. I. 191 Smart L. E. 220 Smit C. J. 160 Smit W. A. 327 Smith A. B. 174 207 273 Smith A. G. 439 Smith A. K. 119 Smith D. M. 111 Smith E. L. 423 Smith G. A. 15,443 Smith G. J. 440 Smith H. W. 416 Smith J. J. 36 Smith K. 136 137 205 Smith K. M. 407 411 419 428 Smith M.R. 75 Smith R. A. 61 Smith R.L. 377 Smith S. G. 401 407 411 Smith T. W. 278 Smith U. H. 429 Snider B. B. 233 Snieckus V. 279 Snow M. R. 281 Snowden R. L. 186 Snyder L. R. 429 Sobnak R. L. 290 Sobell H. M. 17 Soderquist J. A. 149 Soderholm A. C. 280 Sohar P. 277 Solaro R. 110 Soiheim B.A. 375 SolladiC G. 212 Solomon F. 442 Solomon J. D. 369 Solonki B. 268 Solov’ev K. N. 20 21 Solyom S. 277 Somfai I. 234 Sommerfeld C.-D. 168 239 Sondengam B. L. 196 Sondheimer F. 247,248 249 291 Song P. S. 22 23 24 25 28 30 32 34 38 39 Sonnet P. E. 370,371 Sonoda A. 143,189,309,313 Sonoda N. 127,142,189,289 312 Sood H. R. 118 Sorenson R. J. 353 Sotheeswaran S. 216 Soumillion J.P. 223 Souto-Bachiller F. A. 252 Soysa H. S. D. 148 Spackman I. H. 83 Spangler D. 19 Spangler R. J. 115 222 Spear R. J. 80 298 Specchiarelia M. 60 Speltz L. M. 322 Spencer T. A. 108 Speranza M. 223 Spernol A. 101 Spier W. E. 20 Spiegel E. 256 276 Spinelli D. 228 Spinelli P.368 Spira I. 107 Spiro T. G. 22 Springborg J. 281 Springer J. P. 216 375 Sridaran P. 227 Srikrishnan T. 16 Srinivasan R. 220 Staab H. A. 233 235 247 248 Stackhouse J. 150 Stadtmin T. C. 423 Staedler E. 379 Staemmler V. 241 Stafforst D. 199 Staires S. K. 274 Staley R. H. 88 Staley S. W. 306 Stallings W. C. 17 Stang P. J. 118 227 Stanislawski D. 241 Staral J. S. 246 299 300 Stark M. 166 Starr T. L. 13 Starukhin A. S. 20 Staunton J. 397,411 Stavinoha J. L. 171 Steck W. F. 368 369 Steenken S. 95 96 Steevens J. B. 194 Stegk A. 314 Steigerwald H. 123 Stein J. M. 443 Steiner B. W. 3 Steiner P. R. 70 361 Stenzel W. 344 Stepanov B. I.261 Stephan W. 83 Stephenson J. R. 425 Stern R. L. 265 Sternbach L. H. 265 Sternlicht M. 368 Stevens N. R. 222 Stevenson J. M. 271 Stewart A. 119 Stewart R. F. 35 Stewart T. E. 379 Stezowski J. J. 147 Stick R. V. 343 358 Stiles P. J. 180 Still W. C. 150 324 Stipanovic R. D. 190 377 Stirling C. J. M. 183 211 Stock L. M.,225 Stodala R. K. 17 Stoddart J. F. 281 356 Stojanac N. 398 Stoll M. S. 408 Stolle W. T. 310 Stoke R. 239 Stone J. G. 135 Storesund H. 74 Stork G. 288 366 Stout G. H. '3 Strain H. H. 419 Strand A. 248 Strang P. J. 76 Stransky W. 383 385 Stratz G. 433 Strauss H. L. 296 Streck R. 386 Strickland E. H. 34 Strohmeier W. 123 Stroshane R.M. 365 Stroud S. G. 181 Struckmeier G. 16 Stubbe J. 442 Studier M. H. 419 Studzinskii 0.P. 230 Subramanian,R. 358 Suck S. H. 39 Suda M. 62,243 Suess R. 209 Suemitsu R. 128 329 Suenram R. D. 256 Sugie H. 368 Sugimura N. 330 Sugino K. 209 Sugiyama H. 350 Sullivan M. J. 31 Sumengen D. 268 Sumida Y. 275 Summerhays K. D. 216 Summers R. 101 Summerville R. H. 216 Summons R. E. 238 Sun M. 22 34 39 Sundbom M. 20 Suschitzky H. 107 109,264 Sustmann R. 60,69 Sutcliffe L. H. 99 Sutherland I. 423 Sutherland I. O. 66 Sutton M. R. 440 Suzuki A. 335 Suzuki H. 123,126,225 Suzuki M. 257,342,358 Svec W. A. 419 Svensson B. G. 372 Swanson R. 171 Swenton J. S. 232 Swierczewski G. 189 Switzer F.295 Swofford R. L. 29 Sydnes L. V. 111 Symanyk W. 310 Syriopoulus G. T. 341 Szarek W. A. 352 362 364 Szeimies G. 292 Szmant H. H. 354 Taagepera M. 48,273 Taber D. F. 289 Tacconi G. 60 Taft R. W. 7,48 87 216 273 Tagashira Y. 92 Tagat J. 222 Taglieber V. 233 Taguchi H. 107 Taguchi T. 330 Tahara S. 371 Tajima S. 7 Takagi K. 237 Takagi T. 209 Takahashi N. 368 Takahashi,S. 371 Takahashi T. 189 325 366 380,399,425 Takahashi Y. 365 Takahatake Y. 288 Takamuku S. 117 165,290 Takase K. 245 Takata Y. 155 Takaya T. 109 Takegami Y. 320 Takehira Y. 242 Takei H. 330 Takemasa T. 232 Takemura T. 31 Takeshita H. 244 Takeuchi H. 108 Takeuchi K. 72,245 Takeuchi Y. 282 Takigawa T.386 Takken H. J. 338,387 Tal D. 125 Talalay P. 438 439 440 Talbiersky J. 198 Talley P. 176 319 Talman E. 371,373,379 Tam S. Y.-K. 348,349 Tamaki Y. 367,368,369 Tamao K. 229 Tamaru Y. 266 Tamborra P. 205 Tamura Y. 275 Tan H.-W. 100 Tanabe M. 365 Tanaka J. 35 38 Tanaka K. 87,242 Tanaka M. 38,119 Tanaka T. 107 Tanigawa Y. 189 309 Taniguchi H. 99 107 126 Tanimoto S. 106 Tanis S. P. 375 377 Tapia O. 55 Tardella P. A. 109 Tarnowski T. L. 281 Tartar A. 274 Taschenberg E. F. 368 Taschner M. J. 320 Ta-Shma R. 78 Tassi D. 252 Taticchi A. 282 Tatsuki S. 368 Tatsuoka T. 280 Taylor D. R. 183 Author Index Taylor E. C. 147 222 229 277,332 Taylor G. 171 220 Taylor G. L. 17 Taylor L.B. 440 Taylor R. 223,230,240 Taylor R. T. 116 149 187 219,312 Tebby J. C. 3 11 Tedeschi P. 263 Teitell M. F. 39 Temme G. H. 424 ten Hoedt R. W. M. 177 Teranishi A. Y. 192 Teranishi S. 126 Terasawa M. 126 Terashima S. 332 Terent'ev A. B. 90 Terlouw J. K. 5 Tette J. 368 Thackaberry S.P. 92 Thalmann A. 336 Thankachan C. 75,248 Thankwerden B. 182 Thea S. 240 Thebtaranonth C. 276 Thebtaranonth Y.,130 Theissling C. B. 6 273 Thewalt U. 16 Thiel W. 169 Thiem J. 361 Thijs L. 269 Thomas D. R. 107 Thomas J. K. 102 Thomas L. L. 210 Thomas M. G. 135 Thomas P. N. 224 Thomas R. N. 25 Thomas T. M. 30 Thomas W. 230 Thompson A. J. 25 Thompson J. T. 237 Thompson M. 417,427 Thompson R.C. 340 Thompson R. S. 179 Thuillier A. 181 Thulin B. 234 248 Thummell R. P. 221 Tidwell T. T. 75,84,184,189 248 Tigler D. 280 Tikhomirov V. A. 59 Tilden P. E. 372 Tilhard H.-J. 151 Timko J. M. 281 Timm U. 112 Timms P. L. 137 Tinnemans A. H. A. 172,219 Tinoco I. jun. 35 Tishler M. 321 Titova S. P. 239 Tivol W. F. 439 Tobin G. D. 224 Tobin T. R. 371 378 Toda F. 242 Author Index Todd A. R. 423 Todesco P. E. 227 Tokanou H. 109 Tokumaru K. 239 Tokuno E. 330 Toldy L. 277 Tollin G. 39 Tolson T. L. 341 Tornasi J. 46 68 Tornasik W. 198 tom Dieck H.. 126 Tomezsko E. S. 181 Tomioka H. 116 Tomita H. 231 Tomono K. 19 Tonellato U. 178 Tonge K. H. 94 Topol A.77 Toppett S. 256 257 Tori K. 217 Torre G. 197 Toshimitsu A. 189 Toube T. P. 3 Touzin A.-M. 140 Towarowski A. J. 29 Townsend C. A. 424,425 Townsend R. E. 59 Toyne K. J. 216 Toyoda T. 13 Traas P. C. 338,387 Trahanovsky W. S.,222,274 Tramontano A. 143 Trampe S. 233 -Traynor S. G. 215,216,293 Trdatyan V. A. 239 Trefonas L. M. 37 Tremelling M. J. 149 Trenary M. 58 Trickes G. 198 Trifunaq A. D. 103 TrinajstiC N. 215 Trinh-Tgan 163 Trornbini C. 137 Trong Anh N. 60 Trost B. M. 185 207 287 289,336,380,387 Trostman U. 69 Troxler E. 126 Trueblood K. N. 423 Truesdale L. K. 325 Trullinger D. P.,207 Tsai C. C. 17 Tschinkel W. R. 374 Tseng K. L. 231 Tsuchida T. 108 Tsuchiya T. 7 279 365 Tsue Rima T.329 Tsuji A. 273 Tsuji J. 123 189 327 380 381 Tsunetsugu J. 244 Tsuchima T. 192 Tsuzuki K. 378 Tsvetkov Y.E. 347 Tsvirko M. P. 20 Tubault M. 162 Tumlinson J. H. 369 370 376,379 Tunemoto D. 288 Turchi I. J. 169 Turnbull K. 270 Turner J. J. 174,273 Turner R. W. 236 Turner S. P.,9 Turney T. W. 137 Turrell A. G. 229 Turro N.J. 170 308 Tursch B. 367 Tyler R. C. 372 379 Tyrrell H. M. 171 Uchida K. 149 188 Uchida M. 386 Uchikama K. 275 Uchimaru T. 326 Uchiumi K. 368 Uebel E. C. 370,371 Ueda M. 331 Uemura H. 109 179,189 Ueno K. 128 Ukrainskii I. I. 26 Umani-Ronchi A. 137 Umans R. S. 22 Umbreit M. A. 192 320 Umemoto T. 288 Umeyarna H. 51 57 Umezawa H. 365 Umezawa S.365 Umrikhina A. V. 427 Underhill E. W. 368 369 Underwood G. R. 68 Unsworth J. F. 419 Usui T. 365 Utirnoto K. 149,176,188,384 Uto K. 126 Utter M. F. 440 Uwai C. 248 Vagelos P.R. 440 Vaglio G. A. 135 Vakenti J. 368 Valasinas A, 399 403 Valette G. 203 Valeur B. 34 Valle M. 135 Valter W. 255 van Dam H. 194 van de Graaf B. 5 Van Der Avoird A. 46 van der Gen A. 277 Vander Helm R. 14 Vanderpool D. P. 108,109 Van de Sande C. C. 6,8 Van de Vrie M. 369 van Dijck L. A. 182 Van Gaever F. 6 van Haverbeke Y.,7 Vanhooren M.,6 Van Horn D. E. 132,313 van Houte J. J. 4 van Koten G. 177,229 van Leusen A. M. 329 van Leusen D. 329 Van Meerssche M.,254 van Straten J. W.,218,233 Van Telgen H.J. 445 van Thuijl J. 4 van Tilborg W. J. M. 160,258 Van Veen L. jun. 226 Vass G. 363 Vatkle J.-M. 350 Vaughan J. 179 Vedejs E. 280 310 Veeger C. 445 Veillard H. 47 Velthuis H. H. V. 372 Venema A. 7 Venkataramu S. D. 282 Venuti M. C. 237 Verbit L. 3 Vereschchagin L. I. 180 Vergamini P. G. 122 Verhelst G. 257 Verheyden J. P. H. 354 Verhoeven T. R. 207 336 Verkuijlen E. 133 185 Vermeer J. G. C. M. 182 Vermeer P. 141,149,176,313 Vermeulen G. 257 Vernay H. F. 365 Vernon J. M. 274 Verwiel P. E. J. 367,368,371 373,379 Veysoglu T. 212,386 Vial C. 384 Viala J. 318 Vick S. C. 148 150 Victor R. 222 Vidal M. 113 Viehe H. G. 208,252,254 Viger A. 438 VilliCras J. 140 141 Vincens M.113 Vineyard B. D. 122,412 Vinson S. B. 376 Vishveshwara S. 53 Vite J. P. 369 372 378 Vittorelli P.,255 Vivona N. 268 Vogeli R. 243 Vogtle F. 232,233,234,235 Voelter W. 39 Voerrnan S. 367 368,369 Vogel E. 63 168 239 246 249 Vogel F. 143 202 320 Voigt E. 115 Voinova S. E. 261 Volkov V. B. 47 Vollhardt K. P. C. 63 105 119,126,175,220,222,242 3 14 Vollmar A. 225 470 Author Index Volz W. E. 299 Von Dreele R. B. 15 von Schnering H. G. 256 Vorbruggen H. 336 Vorburger T. V. 193 Vos A. 12,258 Vostrowsky O. 369 383 385 Vuilleumier H. 221 Vuturo S. B. 386 Vyas D. M. 362 Wachi H. 239 Waclawski B. J. 193 Wada K. 336 Waddell W. H. 31 32 Wade K. 150 Wade L. E. 65 Wadhams L.J. 372 379 Wadt W. R. 256 Wagemann W. 249 Wagenknecht J. H. 158 Wagner D. 354 Wagniere G. 25 Wah H. K. 275 Waiss A. C. jun. 377 Wakabayashi T. 209 Walborsky H. M. 298 Walker B. S. 127 Walker D. L. 364 Walker D. M. 420 Walker J. A. 64 Wallace B.. 68 192,314 Wallace J. C. 440 Wallace R. G. 105 Wallis C. J. 187 321 Wallis T. G. 60 61 216 Walsh C. T. 433,441 Wan J. K. S. 90 Wancowicz D. J. 196 Wand A. H.-J. 14 Wang V. S. 438 Wang Y. F. 203 Warburg O. 417 Warburton D.. 399 Warren G. B. 443 Warren S. 186 187 211 321 Warrener R. N. 231,243,258 Warshel A. 30 Washburne S. S. 185 Washio H. 378 Washtien W. 435 Wasielewski M. I.,429 Wasserman E. 90 Wasserman H. H. 329 Watanabe Y.244,251 318 Waterhouse I. 65 312 Watson D. R. 355 Watt R. A. 272 Watts R. O. 43 Weatherston J. 367 368,378 379,380,384 Weaver K.M. 376 Webb H. M. 86 Webb J. G. K. 228 Webb K. S. 4 Webb T. R. 200,324 Weber D. 163 Weber G. 34 Weber R. U. 98 101 Weber W. P. 148 Weckerle W. 352 353 357 Weeks C. M. 16 Weese G. W. 5 Wehner W. 235 Wehrli R. 65 Weidlein J. 147 Weigel L. O. 386 Weimann L. J. 20 Weinkam R. J. 8 Weinkauff D. J. 122 412 Weinreb S. M. 208 Weires R. W. 369 Weisgerber H. 268 Weiss C. jun. 19 22 Weissbarth O. 430 Welch J. 202 Weller H. N. 64 307 Weller T. 56 Wells R.J. 397 Welsher T. L. 299 Wender P. A. 166,286,338 Wendisch D. 379 Wendling L. A. 63 Wenham M. J. 372 Wenkert D.287 Wenkert E. 201,287 Wennerstrom O. 234 248 Wentrup C. 114 Wentrup-Byrne E. 114 Weringa W. D. 5 Wescott L. D. jun. 117 Wesdemiotis C. 5,8 West J. R. 379 West P. R. 95 West R. 177,241 Westerman I. J. 60 Westheimer F. H. 432 Westigard P.H. 379 Westley J. W. 194 Westmijze H. 141 149 176 313 Weston A. F. 9 Weston J. B. 224 Weyerstahl P. 202 Weyhenmeyer R. 423 Wheatley C. M. 281 Wheeler J. W.. 367 372 374 White A. H. 152 White C. K. 123 158. 241 White D. N. J. 180 White J. D. 262 336 White J. G. 238,423 White W. N. 237 Whitehead G. 150 Whitehead J. K. 440 Whiter P. F. 182 Whitesell J. K. 197 Whitesell M. A. 197 338 Whitesides G. M. 182 Whitham G. H. 218 296 Whiting D.A. 377 Whiting M. C. 74 75 Whitlock B. J. 138 222 Whitlock H. W. jun. 138,222 Whitten D. G. 19 Whitten J. L. 27 Wiberg K.B. 300 302 Wiberg N. 147 Wichmann J. K. 376,377 Wieringa J. H. 258 Wiersig J. R. 9 Wieser J. D. 231 Wiessler M.,232 274 Wieting R. D. 88 Wightman R. H. 221,397,411 Wihler H. D. 258 Wijsman A. 277 Wilding H. F. 87 Wilkie J. S. 390 Willbe C. 260 Willett G. D. 217 Williams D. C. 398 402,404 419,424,425,421 Williams D. E. 13 Williams D. F. 22 Williams D. H. 3,4 5 15 Williams D. L. H. 237 Williams D. R. 321 336 Williams G. C. 348 Williams G. H. 101 Williams H. J. 317 387 Williams J. C. jun. 158 Williams N. R. 353 Williams P. J. 374 Williams R. N. 374 Williams S.B. 188 313 Williamson A. D. 85 Willing R. I. 390 Willingham A. K. 437 Willis J. P.,157 Willner I. 246 247 249 Willson G. C. 416 Willy W. E. 318 Wilson G. E. 262 Wilson I. F. 311 Wilson J. M. 3 Wilson J. W. 64 231 Wilson N. M. 370 Wilson S. 220 Wilton D. C. 432 Wiltshire J. F. 228 Windel B. 8 Winfield J. M. 109 Winkler H. U. 5 Winkler J. 7 Winkler T. 65 Winnik M. A. 180 Winter J. N 99 Wirtz K. 101 Wirz J. 168 Author Index Wirz P. 377 Withers G. P. 149 319 Witiak D. N. 9 Wittman J. M. 104 Woggon W. D. 378 Wolf R.,272 Wolfschiitz R. 5 Wollenberg R. H. 140 336 Wollowitz S. 109 Woltermann A. 151,201,280 Wong J. 108 128 Wong P. K. 129 Wong R. J. 83 Wong S. K. 167 Woo P.W. K. 355 Wood C. J. 360 Wood D. E. 99 Wood D. L. 372 Wood G. W. 10 Wood H. G. 440,441,442 Wood W. F. 375 Woodgate P. D. 189 Woodward P. 220 Woodward R. B. 62,423 Woolard G. R. 362 364 Wooldridge T. 112,253 Woolfson M. M. 12 Woolhouse A. D. 230 Worley S. D. 47 Wormer P. E. S. 46 Wothermann A. 312 Wrackmeyer B. 144 Wright G. J. 225 Wright T. L. 225 Wrigley N. G. 441 Wudl F. 163 261 Wuest H. 187 Wunderli A. 65 Wursthorn K. R. 151 312 Wurziger H. K. W. 404,413 Wyatt J. 155 Wynberg H. 169,258 Wynberg M. 185 Wyvratt M. J. 294 Yagen B. 424 Yaginuma K. 368 369 Yakakoto K. 327 Yakhontov L. N. 282 Yamabe S. 57 Yamada M. 209,378 Yamada S.,237 Yamada Y. 230,365 Yamaguchi T.280 Yamamoto H. 207 342 Yamamoto I. 109 127 Yamamoto K. 165,233,245 Yamamoto N. 31 Yamamoto Y. 35 143 196 313 Yamamura K. 338 Yamano T. 433 Yamaoka N. 350 Yamaoka R. 367,368 Yamasaki T. 386 Yamashita K. 232 Yamashita M. 128 320 329 Yamaya M. 188 Yamazaki H. 130 Yamazaki I. 23 Yamazaki T. 350 Yamdagni R. 85 Yan C. F. 289 Yanagawa Y. 21 Yanagi J. 165 Yang N. C. 171 Yanofsky C. 443 Yany F. 170,258 Yaouanc J. J. 433 Yarwood A. J. 64,231 Yarwood J. 165 Yasuda D. M. 365 Yasuda H. 381 Yasunami M. 245 Yasuoka N. 13 Yatagai H. 313 Yates K. 84 178 Yavari I. 272 296,360 Yavorskaya A. N. 427 Yee L. S. 242 Yegorova G. D. 21 Yen C. Y. 272 Yengoyan L. 413 Yeo A. N. 9 Yim M.B. 99 Yogo T. 141 Yokomichi Y. 245 Yokoyama K. 203,326 Yokoyama Y. 248 320 335 338 Yoneda N. 181 471 Yoshida J.-I. 229 Yoshida K. 155,230 323 Yoshida S. 368 Yoshida Z.-I.,241,266 Yoshifuji M. 177 313 Yoshikawa S. 126 Yoshikawa Y. 247 249 Yoshimura Y. 217 Yoshino T. 233 Yoshioka T. 242 Young J. C.. 372 Young N. M. 33 Younr M. R.,440 Yu C. C. 256 Yu M. w. 39 Yu N. Y. 22 Yunker M. B. 349,363 Yushima T. 369 Yushkevich N. A. 21 Zaitseva N. I. 427 Zaklika K. A. 258 Zaman Z. 394,412 Zanardi G. 112,253 Zander G. 278 Zapf U. 233 Zaretskii Z. V. 3 Zassinovich G. 123 Zderic S. A. 143 Zehavi U. 322 Zeller E. A. 434 Zeller K.-P. 63 111,112,282 Zembayashi M. 229 Zeppa A. 159 Zettl C.266 Zheltovskii N. V. 36 Zhogolev D. A. 47 Ziegler F. E. 338 Ziegler H. E. 100 Zimmer-Gasser B. 149 Zimmerman H. E. 166 Zumoff B. 437 Zuniga Juaristi G. 272 Zupan M. 172,219,220 Zwanenburg B. 269 Zweifel G. 144,149,317,332 Zwierzak A. 213 321 Zwolinski G. K. 440

ISSN:0069-3030    

DOI:10.1039/OC9777400447

出版商:RSC    

年代:1977

数据来源: RSC