摘要:

Whether proteins denature in an all‐or‐none fashion or in a continuous fashion is as yet an unresolved problem. The all‐or‐none process implies that while the process of denaturation is going on, only two kinds of protein molecules can exist. One is completely unchanged and the other is altered. The altered protein molecules are indistinguishable. Underlying the ‘continuum’ models is the assumption that all the chains in a protein globule undergo similar changes so that it is enough to consider a s

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02839.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Empirical conformational energy calculations were carried out for the dipeptides cyclo‐(L‐Ser‐L‐His) and cyclo‐(L‐Thr‐L‐His). Various DKP structures have been investigated to study side chain conformations through the DKP ring deformations, and prevalent conformers of monosubstituted and disubstituted dipeptides are discussed. The most stable conformations occur when both side chains are folded over a planar DKP ring, the imidazole ring being in the ε‐tautomeric form.Theoretical results are consistent with those obtained from n.m.r. and crysta

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02840.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

This paper demonstrates the existence of regions in eight small globular proteins in which the side chains of sulfur‐containing amino acids (cysteine and methionine) alternate in space with side chains of aromatic amino acids (histidine, phenylalanine, tryptophan and tyrosine). The proteins are: rubredoxin, high potential iron protein, cytochrome c, flavodoxin, deoxyhemoglobin, trypsin inhibitor, ribonuclease‐S, and lysozyme. The sulfur‐φ‐bonded ‘chains’ involve a minimum of five and a maximum of 10 amino acids, and contain the most polarizable atoms within proteins. S‐φ‐chains give extra stability to the folding of proteins; they may also afford paths for the step‐wise mo

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02841.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A description is given of the synthesis by fragment condensation of the peptide Gly‐Glu‐Ser‐Arg‐Glu‐Ser‐Ser‐Ala‐Asp‐Lys‐Phe‐Lys‐Arg‐Gln‐His‐Met‐Asp‐Thr‐Glu‐Gly‐Pro‐Ser‐Lys corresponding to the 1–23 amino acid sequence of rat pancreatic ribonuclease. This rat peptide combined with bovine S‐protein

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02842.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The location of the four disulfide bridges in cardiotoxin from the venom of the Formosan cobra, Naja naja atra, was determined by isolating cystine‐containing peptides from the enzymic and partial acid hydrolyzates of the intact toxin. The results indicate that the disulfide bridges are formed by half cystine residues 3–21, 14–38, 42–53, and 54–59. The amino acid sequence at the position 48–49 was revised to ‐Leu‐Val‐ instead of ‐Val‐Leu‐

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02843.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The synthesis of apamin, the principal neurotoxin in bee venom, has been accomplished by the solid phase method on a benzhydrylamine resin. 2‐Phenylisopropyloxycarbonyl amino acids were used throughout the synthesis except for the C‐terminal histidine. Improved yields in the coupling steps in the N‐terminal part of the molecule were obtained by coupling each amino acid both in dichloromethane and dimethylformamide. The use of acetamidomethyl as an S‐protecting group for cysteine made it possible to isolate and purify the linear peptide. The deblocked and oxidized peptide was fractionated by ion‐exchange chromatography (Bio‐Rex 70) to obtain a highly purified apamin with full biological activity and with the same physical and chemical properties as the natural peptide. Circular dichroism (CD) spectra of the synthetic and natural apamin wer

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02844.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Nα‐9‐Fluorenylmethyloxycarbonyl (Fmoc) amino acids will be of advantage in solid phase peptide synthesis. The Fmoc‐group is quantitatively cleaved by mild base (piperidine). This permits the use of tert‐butyl‐type side chain blocking and of peptide‐to‐resin linkage cleavable by mild acidolysis. Side reactions arising from repetitive acid deprotection and final HF cleavage in contemporary solid phase synthesis are avoided. Fully bioactive and homogeneous dihydrosomatostatin was obtained in 53%

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02845.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1978.tb02846.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY