摘要:

A normal mode calculation has been done for Pro‐Leu‐Gly‐NH2in its crystalline type II β‐turn structure, and assignments have been made to infrared and Raman bands of this molecule and itsN‐deuterated derivative. Observed and calculated frequencies below 1700 cm‐1agree to within about 6 cm‐1. This analysis provides a sound basis for studying the conformation dependence of the vibrat

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02686.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Acetylated and succinylated arachins were examined for various physico‐chemical parameters such as viscosity, absorption and fluorescence spectra, gel electrophoretic patterns, gel filtration profiles and susceptibility to proteolysis. Acetylation and succinylation lead to dissociation of arachin into lower molecular weight fractions. The lower molecular weight fractions had a higher degree of succinylation compared to other fractions. The absorption and the fluorescence spectra were perturbed both by acetylation and by succinylation. Both fluorescence and viscosity data indicate denaturation of acylated arachins. The modified arachin was more susceptible to proteolysis by trypsin and chymotrypsin and varied in degree of hydrolysi

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02687.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Upon long standing and very slow evaporation, a solution of the cyclic penta‐peptide and Mg(SCN)2in CDCl3/CD3CN produced colorless crystals of a 1:1 complex of the peptide and Mg++. X‐ray diffraction analysis showed the contents of the asymmetric unit to be C24H31N5O5˙ Mg++˙ NCS‐˙ HSO‐4˙ 6H2O (P212121, a = 8.444 (1) A, b = 10.735 (2) A, c = 39.726 (6) A). This first example of a metal ion complex with a cyclic pentapeptide is in the form of an infinite stack with alternating peptide and Mg++moieties. The octahedrally coordinated Mg++makes only two ligands with the peptide carbonyls: O(3)—Mg++above and O(1)—Mg++below. The equatorial coordinations involve three H2O molecules and NCS‐. There is a profound change in conformation upon complexation, with several ø and ø values changing by 90° to 230°. One NCS‐oxidizes to HSO‐4t

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02688.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Two analogs of the red pigment‐concentrating hormone (RPCH) have been synthesized by the solid‐phase method: [Thr6]‐RPCH (I) and [Tyr4, Thr6]‐RCPH (II). Analog I has the same amino acid composition as the second adipokinetic hormone (AKH‐II) isolated from locust corpora cardiaca. Bioassay for lipid‐mobilizing activity in adult male locusts gave the following increases in hemolymph lipid content: AKH‐I, 3.5; I, 2.4; II, 2.9. The biological response shown by I lends support to the conclusion that its sequence is that of the presumptive AKH‐II. Replacement of Phe in position 4 by Tyr does not reduce the adipok

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02689.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Synthesis of ostrich and turkey corticotropin (ACTH) has been accomplished by the solid‐phase method. Each was identical to the natural hormone in high performance liquid chromatography. Relative potencies in a lipolytic assay in isolated rabbit fat cells were: human ACTH, 100; ostrich ACTH, 53; turkey ACTH, 28. In isolated rat fat cells relative lipolytic potencies were: human ACTH, 100; ostrich ACTH, 2; turkey ACTH, 13. It was concluded that lipolytic potency is sensitive to alterations in structure throughout the entire length of the ACTH sequence in the rat fat cell assa

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02690.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A solid‐state and solution analysis of the homo‐oligopeptides from ε‐tert.‐butyloxycarbonyl‐L‐lysine withp‐oxymethylbenzylcholestan‐3β‐yl succinate asC‐terminal group, using infrared absorption and circular dichroism, is described. The occurrence of intermolecular β‐structure is seen in the solid state and in solvents of low polarity, e.g. methylene chloride, for peptides of intermediate size (from pentamer to decamer). Conversely, the eicosapeptide exhibits a high percentage of α‐helical structure both in the solid state and in 2, 2, 2‐trifluoroethanol. The influence of theC‐terminal group on the conformational preferences of the ε‐blocked homo‐oligolysines in the solid state and in

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02691.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

tert.‐Butyl amino carbonate (1,tert.‐butyloxycarbonyloxyamine) was prepared by reaction of hydroxylamine with di‐tert.‐butyl dicarbonate (2). 1 was used to acylate different amino acids or amines in water or in aqueous dioxane. 1 was also preparedin situand used to acylate amino acids directly. 1 reacted 1.5–2.5 times faster than 2 with all amines studied either in water or 50% (v/v) dioxane. Remarkably, 1 retained its ability to acylate amines even in acid solution; the rate of acylation of L‐Phe at pH 6.5 (15 M‐1˙ min‐1) was about 20% of the rate at pH 10 (72 M‐1˙ min‐1). 2 was not an acylating reagent below pH 7.0 and as expected, the rate at pH 8.3 (4 M‐1˙ min‐1) was about 10% of that at pH 9.3 (39 M‐1˙ min‐1). Pure BOC‐amino acids were obtained in high yield and could be quantitatively d

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02692.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The S‐peptide of the enzyme bovine pancreatic ribonuclease has been used as a model for covalent semisynthesis. Methods for side‐chain protection, enzymatic cleavage of the peptide chain at the level of the single arginine‐10 and for selective deprotection of the α‐carboxyl function of this residue, have been examined. The partially protected [1–10] sequence has been coupled to a solid‐phase generated [11–15]sequence attached to the polymer. After deblocking from the solid‐support, the [1–15] semisynthetic peptide was complexed with native S‐protein to give a complex with high

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02693.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The photoreactive arylsulfenyl chloride 2‐nitro‐4‐azidophenylsulfenyl chloride (2,4‐NAPS‐Cl) has been used for the selective modification of tryptophan in Kunitz's soybean trypsin inhibitor (SBTI). The ultraviolet absorption spectrum and amino acid analysis of 2,4‐NAPS‐SBTI indicated that only one of the two tryptophans (93 or 117) present in SBTI was modified. CNBr cleavage of 2,4‐NAPS‐SBTI resulted in two fragments 1–114 and 115–181.Amino acid analysis of the two separated fragments showed that only tryptophan 93 underwent modification. 2,4‐NAPS‐SBTI fully retained its inhibitory activity against trypsin. The photoaffinity labeling of trypsin with 2,4‐NAPS‐Cl was performed on tritiated trypsin prepared by reacting bovine trypsin with [3H]‐succinimidyl propionate. The covalent attachment of 2,4‐NAPS‐SBTI to the tritiated trypsin after photolysis was demonstrated by exclusion chromatography on Sephadex G‐50 in th

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02694.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Substituting sarcosine orN‐methylalanine for proline in the inhibitory vasopressin analogs dPAVP and d(CH2)5AVP had the following effects: 1) milk ejection and antidiuretic activities were severely depressed, 2) pressor antagonism was maintained but weakened somewhat, and 3) antagonism in the uterusin vitrowas maintained, but no consistent pattern was see

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1984.tb02695.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY