摘要:

The syntheses of equine β‐melanotropin and newly isolated des‐Asp1‐β‐melanotropin are described. The syntheses have been accomplished by the solid‐phase method. The lipolytic potency of des‐Asp1‐βe‐MSH is about 5 times higher t

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02611.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Substitution of Pro residues with AIB (α‐aminoisobutyric acid) residues in peptides provides a means of evaluating the presence ofcis'proline conformations both in solution and, using bioassay data, in a receptor complex.1H n.m.r. has been used to probe the DMSO solution conformation of all seven of the possible AIB/Pro isomers of bradykinin. AIB substitution for Pro2and/or Pro3appears to stabilize a type III β‐turn involving theN‐terminal residues, but not an incipient 310helix suggested by model peptides. These substitutions are correlated with low biological potencies, suggesting that such conformational features may be incompatible with receptor complexation. Alternatively, AIB7‐bradykinin analogs exhibit a variety of long range shift perturbations relative to bradykinin. The data suggests that bradykinin can adopt several folded conformations, including β‐turns involving both Ser6‐Pro7‐Phe8‐Arg9and Phe5‐Ser6‐Pro7‐Phe8. The relatively high biological activities of the AIB7‐BK suggest that the complexed form of the peptide is characterize

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02612.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A β‐endorphin‐(1–27)‐like peptide was isolated from bovine cerebral hemisphere extracts by gel filtration, ion‐exchange chromatography, high performance liquid chromatography and paper electrophoresis. The peptide had tyrosine as the amino‐terminal residue and its amino acid composition was nearly identical to that of equine pituitary β‐EP‐(1–27). It had also the same mobility as equine pituitary β‐EP‐(1–27) in paper electrophoresis. In radioimmunoassay and opiate receptor‐binding assay, the brain peptide had 50% activity when compared with human β‐endorphin‐(1–27). Evidence for the occurrence of NH2‐acetylated form of

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02613.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A double‐headed analog of human β‐endorphin (βh‐EP),N, N'‐bis(β‐endorphinyl)‐cystine (II), has been synthesized by the solid‐phase method, along with βh‐EP‐Cys(CH2CONH2)‐OH (I) and (Tyr31]‐βh‐EP (III). Their relative potencies in a radioreceptor‐binding assay were: Bh‐EP, 100; II, 235; I, 170; and III, 204. In the tail‐flick test for analgesic activity their relative potencies were: βhE

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02614.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A quantitative study of the degree of racemization induced by the [(NH3)5Co‐(III)‐] protecting group when bound to theC‐terminal of the amino acids Leu, Phe, and His, ashas been carried out. Racemization was determined by forming the diastereomeric cobalt dipeptides [(Leu)(AA)Co(III)(NH3)5] where AA = L‐Leu, L‐Phe, and L‐His; after cobalt removal (using NaBH4), the peptide diastereomers were analyzed quantitatively using an amino acid analyzer. No racemization was observed within experimental error (0.3%) as a result of the substitution of the [(NH3)5Co(III)‐] group on the amino acids and pep

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02615.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Stimulation of corticosterone and aldosterone production in rat adrenal decapsular and capsular cells respectively by α‐ and β‐melanotropins (α‐ and β‐MSH) have been investigated. Although they are considerably less potent than corticotropin (ACTH), the dose‐response curves are parallel to those for ACTH except in the case of aldosterone stimulation by β‐MSH where the dose‐response curve is biphasic. The steroidogenic actions of ACTH, β‐MSH and α‐MSH are antagonized by corticotropin‐inhibiting peptide in both capsular and decapsular cells. A synthetic analog of β‐MSH ([Gly10]‐βe1‐MSH) inhibits both β‐MSH and ACTH in aldosterone output in capsular cells, but it does not inhibit their corticoster

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02616.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The hypothalamo‐neurohypophyseal hormones of the brush‐tailed possum (Trichosurus vulpecula) have been purified through molecular sieving and paper chromatoelectrophoresis. Two peptides have been isolated, one with pressor property, the other with uterotonic activity. The pressor hormone has been identified asarginine vasopressinby amino acid composition and amino acid sequence. The oxytocin‐like hormone has been characterized asmesotocinby amino acid composition. The amounts per dried neuro‐intermediate gland (1.0–1.5 mg) are approximately 12 and 5 nmol, respectively.Up to now, mesotocin has only been found in non‐mammalian tetrapods, particularly in reptiles. Its preservation in Australian marsupials (MacropodidaeandPhalangeridae), and the replacement of vasotocin by a vasopressin‐like peptide, suggests that they are transition species between reptiles and Eutheria. However, the presence of mesotocin raises the question of its role in marsup

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02617.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Inhibitors of neutral ribonuclease have been purified to homogeneity from beef, pig, sheep, mouse, and rat liver by affinity chromatography on Sepharose‐RNase A with overall yields ranging from 60–80%. Each of the purified inhibitors presents a single band by SDS‐gel electrophoresis; molecular weight estimates by SDS‐gel electrophoresis and by gel filtration are ca. 50000. Each of the inhibitors forms a complex with beef pancreatic RNase A with a molecular weight of ca. 64000, suggestive of 1:1 binding on a molar basis. The inhibitors from liver are very similar in properties and amino acid composition to the previously isolated inhibitor from human placenta (Blackburnet al.(1977)J. Biol Chem.252, 5904) and beef brain (Burtonet al.(1980)Int. J. Peptide Protein Res.16, 359). Pig liver offers an alternative to human placenta as a source for an RNase inhibitor of this type (yield, ca. 8 mg/kg of tissue). Immunological similarities were examined using antiserum directed against human placental RNase inhibitor. Cross reactivity of the liver RNase inhibitors with the antiserum raised against placental RNase inhibitor ranged from 15% for mouse RNase inhibitor to as low as 2% for pig and sheep RNase in

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02618.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The compositional distribution of the twenty amino acids was examined for particular positions within secondary structures (α‐helices, β‐strands, and turns) taken from a 44‐protein sample. Correlation coefficients calculated between positional composition of the amino acids and various of their physico‐chemical characteristics indicated considerable asymmetry in the properties of the residues comprising regions within and adjacent to secondary structures, modes of helix formation, physical parameters most sensitive to the buriedness of residues in β‐strands, and posssible improvements in the accuracy of secondary structure prediction m

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02619.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A secondary structure prediction technique is proposed which includes nucleation site determination through multiplication of conformational preference parameters as well as weighting factors to represent structurally stabilizing short range interactions. The prediction accuracy of the method is calculated using data bases categorized according to the four protein structural classes and with differing assignments of secondary structural regions. The results indicate that nearest neighbor prediction techniques (a) are insensitive to various assignment criteria for the secondary structural spans, (b) have nearly achieved their upper limit of prediction accuracy, and (c) can be somewhat improved through the use of stereochemical weighting factors and conformational parameters derived from the four structural groups.

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb02620.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY