摘要:

Various S‐substituted derivatives of the reduced low sulphur and high sulphur proteins from wool have been prepared in which the substituted group is hydrogen, carboxymethyl, carboxyethyl, methyl, carbamidomethyl, cyanoethyl and aminoethyl. The proton magnetic resonance (PMR) spectra and gel filtration chromatography of these proteins have been examined in 8 M urea solution as a function of pH in order to determine conditions under which the proteins occur as random coils in solution with no evidence for the occurrence of non‐covalent interactions.The PMR method described in an earlier paper (1) provides an easier and much more sensitive method for the observation of non‐covalent interactions in random coil proteins than does the measurement of elution volumes in gel chromatography. The results obtained by both methods are consistent and show that the widest range of pH for which unfolding occurs in 8 M urea is obtained with the S‐carboxymethyl, S‐carboxyethyl, S‐methyl and S‐carbamidomethy

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02433.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Gelatin or poly‐L‐tyrosyl gelatin shows extensive degradation when exposed to ultraviolet radiation at a wavelength of 230 nm. Bovine serum albumin, a globular protein, exposed either to such ultraviolet radiation or to γ‐irradiation in the solid state resists the photolysis of peptide bonds. Molecular weights are determined by the ultracentrifugal “low speed” sedimentation equilibrium method. The effect of different speeds on the apparent average molecular weight of heterogeneous material is clearly i

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02434.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

The esterification of Ribonuclease‐A in methanol/0.1 M hydrochloric acid has been studied by measuring the decrease in the number of titratable groups of the protein and estimating the amount of methanol incorporated. Esterification of nearly five of the 11 free carboxyl groups of the protein resulted in almost complete inactivation of the enzyme. The initial products of esterification have been chromatographed on Amberlite columns, and five partially active methyl ester derivatives of Ribonuclease‐A have been isolated. The dimethyl ester, the initial product of esterification with reduced catalytic activity, has the carboxyl groups of Glu‐49 and Asp‐53 modified. Even in the non‐aqueous solvent, as in the native structure of the protein in aqueous solution, these carboxyl groups are the fast reacting ones. Subsequently, the esterification reaction appears to proceed preferentially at the C‐terminal region of the molecule. Comparison of the reactivities of carboxyl groups of Ribonuclease‐A in acidic methanol to that known in aqueous solutions (with carbodiimides) suggests that the structure of Ribonuclease‐A in the non‐aqueous solvent resembles, at least in part, the structure in aq

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02435.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Syntheses of (Pro‐Leu‐Gly)nand (Leu‐Pro‐Gly)n, two synthetic polytripeptide analogues of the non‐polar regions of collagen,viathe corresponding tripeptide p‐nitrophenyl‐esters are described.The sequential polypeptide (Pro‐Leu‐Gly)10was also obtained by solid‐phase synthesis.In the following paper, conformational investigations on these polymers, both in solution and in solid state

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02436.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Syntheses of the sequential polypeptide elastin models poly‐(Gly‐Val‐Gly‐Val‐Pro) and poly‐(Gly‐Val‐Pro‐G

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02437.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

A general route has been devised for the synthesis of sequential polypeptide collagen models of formula H‐(X‐Gly‐Pro)n‐OH where X is a trifunctional amino acid residue. Application of this route to the cases X = Tyr, Orn, Lys, Glu and Ser is de

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02438.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Seven carboxy modified and four amino modified derivatives of human serum albumin have been prepared and studied by optical rotatory dispersion measurements, gel filtration, immunoelectrophoresis, immunodiffusion and by use of an ammonium sulphate technique. It is found that carboxy groups are of major importance for the maintenance of the structure and function of human serum albumin, and that carboxy modification has a much more profound effect than amino modification has to the same relative extent.

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02439.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Penicillinase (E.C.3.5.2.6) fromBacillus cereus569/H is inhibited by Hg(II). The inhibition is characterized by non‐competitive kinetics and can be reversed by EDTA. A Hg(II) induced conformational change is indicated because: (1) The EDTA regenerated activity is unstable and is rapidly converted to an iodine‐sensitive state, and (2) An irreversible change in the circular dichroism spectrum at 222 nm is fo

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02440.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Various methods of preparing human kininogen were investigated with an aim to limit the immunoreactive contaminant proteins to permit purification by immunosorption. A five‐step procedure is described giving 7.5% yield of highly purified kininogen (pharmacological purity 14–20) from pooled human plasma, and containing approximately 30% alpha‐2HS‐glycoprotein and 2.8% albumin. Alpha‐2HS could not be removed by polyacrylamide gel electrophoresis or isoelectric focusing in column.Analysis of heterogeneity of kininogen after chromatography on DEAE‐Sephadex using various linear gradients and gel filtration on Sephadex G‐100 suggested that a minor component may be an aggregate, not included in the yield. It remains uncertain whether this component derives from an occasionally observed high molecular form of active kininogen in the primary purification steps in the 7–12 S sieve fractions from Sephadex G‐200, and excluded from further purification by pooling.Purification with immunosorbents was investigated using batch operations with antibody specific polymers prepared with antisera insolubilized with ethylchloroformate. It was found that the adsorption‐desorption procedure was favourable for immunization purposes in producing highly specific immunologically pure kininogen. The kininogen obtained by this method or by the removal of contaminant alpha‐2HS and albumin with the corresponding antibody specific polymers gave similar heterogenous patterns by polyacrylamide gel electrophoresis, indicating a main band of kininogen and several faintly stained bands which responded only to anti‐kininogen. With 200 μg of the kininogen protein purified by immunosorption using monospecific antiserum the kininogen precipitation titre was 1:8 after 6–8 weeks in rabbits. With a polymer prepared with 4 ml anti‐kininogen serum (1:8) and incubated with 800 μg highly purified kininogen approximately half the protein was desorbed with 2 M and 3 M sodium iodide in the first ad

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1975.tb02441.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY