摘要:

Main chain conformation characteristics of the respective side chains of the 20 naturally occurring amino acid residues were obtained by the analysis of (φ, ε)‐data from the crystal structures of 38 different globular proteins. The following observations are of interest: (i) For amino acids other than Glu, Thr and aliphatic amino acids, at least one main chain conformation is stabilised solely by side chain atoms. Such conformations are listed. (ii) In globular proteins, the main chain conformations which are significantly destabilised by side chain atom interactions are observed. The stabilising force for those conformations seems to come from main chain atom interactions. (iii) A set of conformations for which the main chain and side chain interactions are almost equal but in opposite directions, is listed and these conformations will be taken by residues mainly due to the effect of surroundings.The results can be used to study the folding of polypeptide chains and they also provide an insight into the role of the respective side chains on main chain conformations of amino acid resid

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03016.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The presence and secretion of immunoreactive dynorphin in bovine adrenal medulla and isolated adrenal chromaffin cells were examined and compared with those of immunoreactive leucine‐enkephalin. Using an antiserum raised against dynorphin‐(1–13), a sensitive and highly specific radioimmunoassay was developed. A nearly intact antigen was required for recognition by the antiserum since it did not react with leucine‐enkephalin and reacted poorly with dynorphin‐(1–12) (cross‐reactivity 0.5%) and other fragments of dynorphin‐(1–13). On the other hand, the antibody used for detection of leucine‐enkephalin did not cross‐react with dynorphin‐(1–13). Adrenal medulla acid extracts contained 195 times more immunoreactive leucine‐enkephalin than dynorphin. However, the concentration of immunoreactive dynorphin in acid extracts of freshly isolated adrenal chromaffin cells was only 1.4 times smaller than that of leucine‐enkephalin. Incubation of the isolated chromaffin cells in the presence of acetylcholine, nicotine, high potassium, but not muscarine, induced a concomitant release of immunoreactive dynorphin (3.5–9% of total cell content) and leucine‐enkephalin

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03017.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Two highly potent dynorphin‐like peptides were isolated from bovine adrenal medulla by successive chromatography of an acid (HCl) extract on Sephadex G‐10, carboxymethylcellulose, Sephadex G‐50 and partition chromatography on Sephadex G‐50. Amino acid analysis of both peptides revealed the presence of 24 amino acids including the composition of dynorphin‐(1–13) and differing from each other only by a few residues. Both peptides were shown to have the same activity as dynorphin‐(1–13) in the guinea pig ileum assay and reacted as well as dynorphin‐(1–13) with a specific antibody (R‐31) directed against t

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03018.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The thermal denaturation of lysozyme in aqueous sulfoxide solutions (pH 3) was investigated by differential scanning calorimetry (DSC). The sulfoxides employed were dimethylsulfoxide (DMSO), ethylmethylsulfoxide (EMSO), diethylsulfoxide (DESO), and butylmethylsulfoxide (BMSO). The temperature of denaturation, Td, decreased with an increase in the concentration of sulfoxide, the decrease becoming much more pronounced at higher sulfoxide concentrations. The lowering of Tdwas enhanced by an increase in the hydrocarbon content of the sulfoxide molecule. The enthalpy of denaturation, ΔHd, showed a complex dependence on the solvent composition; the ΔHdfirst increased with increasing sulfoxide concentration and then started decreasing at different concentrations for each sulfoxide. This behavior is analogous to that with monohydric alcohols, but is different from that with guanidine hydrochloride. These results may be interpreted in terms of the interactions of the sulfoxide added with the protein and with wate

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03019.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The following amino acid sequence of the small cyanogen bromide peptide (mol. wt. 5399) of thermitase fromThermoactinomyces vulgarishas been determined: Ala‐Thr‐Pro‐His‐Val‐Ala‐Gly‐Val‐Ala‐Gly‐Leu‐Leu‐Ala‐Ser‐Gln‐Gly‐Arg‐Ser‐Ala‐Ser‐Asn‐Ile‐Arg‐Ala‐Ala‐Ile‐Glu‐Asn‐Thr‐Ala‐Asp‐Lys‐Ile‐Ser‐Gly‐Thr‐Gly‐Thr‐Tyr‐Trp‐Ala‐Lys‐Gly‐Arg‐Val‐Asn‐Ala‐Tyr‐Lys‐Ala‐Val‐Gln‐Tyr.The results obtained support the classification of the enzyme as a serine proteinase of the subtilisin type as proposed in a previous paper (1). This partial sequence extending from the serine residue involved in the active site to theC‐terminal amino acid of the enzyme shows a 40% homology with the corresponding part of the subtilisin BPN' or subtilisin Carlsberg molecule but a 56% homology as regards conservative amino acid replacements.The secondary structure of this polypeptide fragment, predicted from the data obtained by the method of Chou&Fasman (2) agrees fairly well, within the limit of error of the method, with the structure of the corresponding part of the subtilisin BPN' molecule. Therefore, as expected, no dramatic changes in the spatial structure appea

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03020.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The products of spontaneous and induced proteolysis of human ceruloplasmin (Cp) were studied. Some physico‐chemical properties of the six fragments with electrophoretically determined Mr 13 0000 (F1), 110000 (F2), 66 000 (F3), 48 000 (F4) 22 000 (F5) and 18 000 (F6) were compared. The amino acid compositions andN‐terminal amino acid sequences coincide in F1–F5, but differ from those of F6. Limited tryptic proteolysis of Cp causes the accumulation of polypeptide fragment with Mr 22 000, theN‐terminal primary structure of which is identical to that of F5produced by spontaneous proteolysis. Electrophoretic fragments of Cp were extracted from polyacrylamide gel, treated with125I and then studied by peptide mapping with subsequent radioautography. The comparison of the “finger prints” showed the identity of F1to F2and F3and gross similarity between F4and F1– F3. It also revealed similar peptides in F5and F6hydrolyzates and almost perfect matching of the F4map to the map of F5+ F6mixture. On the basis of the obtained data general principles of Cp molecular organization are discussed and intramolecular homology is suggested to be a feature o

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03021.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

[ΔAla2, Leu5]‐enkephalin has been prepared and shown to be more active than the parent saturated enkephalin in a binding assay using rat brain membranes and [3H] dihydromorphine as a tracer. In a comparison of potencies against [3H] dihydromorphine and [3H]‐[d‐Ala2,d‐Leu5]‐enkephalin as tracers, [ΔAla2, Leu5]‐enkephalin showed preference for μ opiate receptors, possibly due to the hydrophobicity of the ΔAla2residue. A synthetic tetrapeptide enkephalin [ΔAla2]‐desLeu5‐enkephalin had weak activity and high selectivity for the μ receptors.O‐Acylation of a serine residue in the peptide was achieved by coupling between the peptide and a carboxylic acid using DCC and a catalytic amount of

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03022.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The thermal denaturation of human choriomammotropin and ovine prolactin in 0.1 M tris‐Cl buffer, pH 8.2, is a simple endothermic process which is at least partially reversible, and does not produce coagulation of the proteins. The transition temperatures suggest fairly stable conformations for these two proteins, but their enthalpies of denaturation are unusually low. The thermal denaturation of human somatotropin begins as an endothermic event with a considerably greater enthalpy of denaturation and a transition temperature higher than that of the other two hormones. However, before the endothermic portion of the denaturation can be completed, the human somatotropin coagulates, producing a powerful exothermic heat flo

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03023.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The chromatographic behaviour of the dansyl‐dipeptides likely to be encountered in manual dansyl‐Edman sequencing is presented. The dansyl dipeptides were either encountered in experimental sequencing or chemically synthesised and in some cases both. The advantages of using short hydrolysis times and deliberately generating these dipeptides are discus

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03024.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The octacosapeptide amide corresponding to the entire amino acid sequence of chicken vasoactive peptide (VIP) was assembled on ap‐benzyloxybenzylamine resin support using the base‐labile 9‐fluorenylmethyloxycarbonyl asNα‐protecting group, cleaved by mild acid treatment, and purified by gel‐filtration and ion‐exchange chromatography. The symmetrical anhydride coupling was employed and monitored by two independent methods, and acetic anhydride termination was incorporated to minimize formation of deletion peptides. The homogeneity of the final product, obtained in 18% yield, was assessed by t.l.c., disc electrophoresis, amino‐terminal amino acid analysis, and amino acid analyses of acid and enzyme hydrolysates. The purified chicken VIP was shown to be active on gastric acid secretion and on pancreatic blood flow. Previously reported ring closure of the Asp‐Asn unit seemed to be at a minimum, owing to the mild basic and

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1982.tb03025.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY