ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01829.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01830.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

When the primary structure of bovine trypsinogen is searched for the existence of regularities, according to Greller&Erhan (1974), one finds eight pairs of peptides, arranged in a symmetrical pattern along the molecule. These peptides cover 49% of the length of the molecule–112 of the 227 amino acids – and each pair folds in a similar way. This observation is in agreement with the observation that “Trypsin folds into two halves, each of which contains a pseudo‐cylindrical arrangement of hydrogen bonds…”, Stroudet al.(1971). Thus the above mentioned method is capable not only of detecting regularities along the primary structure but also of predicting the folding o

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01831.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A method is described for isolating conarachin II in a homogeneous form by the techniques of DEAE‐cellulose chromatography, polyacrylamide gel electrophoresis and sedimentation velocity. The protein contains 0.72% carbohydrate and no phosphate. Hydrogen ion titration curve indicated that the sidechain carboxyl, imidazole and ‐amino groups titrated with normal pKIntvalues and their number agreed with the analytical values obtained from amino acid analysis. However, tyrosine phenolic groups had abnormal pKIntof 1

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01832.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Carbobenzoxy‐D‐phenylalanyl‐triethylenetetramine‐Sepharose (Z‐D‐Phe‐T‐Sepharose) was found to be an effective affinity adsorbent for several proteolytic enzymes which preferentially catalyze the hydrolytic cleavage of peptide bonds involving amino or carboxyl groups of hydrophobic and bulky amino acid residues. α‐Chymotrypsin, subtilisin and neutral metalloendopeptidase were adsorbed at pH 5–7, while pepsin andRhizopus niveusacid protease showed affinity to the adsorbent at pH 3.5–5.0. α‐Chymotrypsin was recovered by elution with 0.1 M acetic acid and neutral subtilopeptidase (B. subtilisneutral protease) was eluted with 0.5 M NaCl at pH 9.0. Subtilisin and thermolysin were found in the eluates with 1.5 M guanidine‐HCl, 1 Mp‐toluenesulfonate or 30% ethylene glycol at pH 7.Rhizopusacid protease was eluted with 0.5 M acetic acid and pepsin with 1 M guanidine‐HCl or p‐toluenesulfonate at pH 3.5. The chromatographic purifications by this method of highly purified or crystallized enzyme preparations commercially available resulted in 1.3–1.5‐fold increase in their specific activities. Inactivation of these proteolytic enzymes by chemical modification, and formation of enzyme‐inhibitor complex led to loss of the binding ability to the adsorbent. On the other hand, the zinc‐free apoenzymes of neutral subtilopeptidase and thermolysin were adsorbed onto and eluted from the adsorbent column under the same conditions as those for the native enzymes, suggesting that zinc is not essential for the binding o

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01833.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Some geometrical parameters associated with the donor and the acceptor end of O‐H…O hydrogen bonds have been analysed. The data consist of 356 hydrogen bonds from reported crystal structures of amino acids, peptides and oligosaccharides. The following conclusions are arrived at:(a) The most probable range for the hydrogen bond length is between 2.7–2.8 å, the average being 2.76 å. When the donor is a water molecule the distribution is slightly different from the other cases. The average becomes 2.82 å, indicating that O‐H…O hydrogen bonds, where a water molecule acts as a donor, tend to be slightly larger.(b) The maximum in the distribution for the hydrogen bond angle (H‐O‥ .O) lies in the range 5°–10°, indicating that the O‐H…O hydrogen bonds tend to be slightly nonlinear, a feature similar to that for N‐H…O hydrogen bonds.(c) For carbonyl type of acceptor groups, the distribution of angle between O‥ .O (or H…O) and C = O extended shows a maximum in the range 50°–60° indicating a directional property towards the lone pair electrons.In order to study the effect of lone pair orbitals on the direction of orientation of the O‐H group the following parameters connected with the direction of lone pair orbitals are analysed and the main results are:(d) The elevation of O‥ .O (and H…O) direction from the acceptor plane (plane containing the lone pair orbitals), (ζ), shows a maximum in the range O°–10° indicating that the direction thus tends to lie close to the acceptor plane. For carbonyl acceptor groups, the distribution is uniform up to 30° and many of the larger values of ζ are found to occur for carbonyl acceptor groups only.(e) The distribution for the angle between the projection Oaccep.…Odonor(and Oaccep.…H) direction on the acceptor plane and the direction of the lone pair orbital (ζ) shows a maximum in the range O°–30°. The distribution is found to be dependent on thenumberof hydrogen bonds for which the same oxygen atom is the acceptor. The distribution for ζ shows a maximum between 20°–30° for those cases when the oxygen atom is recipient of only one hydrogen bond and the maximum occurs between O°–10° for those cases when the oxygen receives two hydrogen bonds.(f) The geometry in the limited number of examples where th

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01834.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The sequence of tropomyosin contains 13 out of the 14 residues necessary to form a set of seven pairs of charged groups repeating at intervals of 57 å. These pairs could be involved in the interaction of tropomyosin with actin

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01835.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Application of the 2‐methylsulfonylethyloxycarbonyl group for temporary amino protection enables the synthesis from one precursor of des‐Nα1‐acetyl‐α‐MSH, the two mono N‐acetylated forms (in positions I and II) and the diacetyl form of this tridecapeptide amide. The free tridecapeptide amide, although structurally unrelated to the normal substrate, was recognized by an enzyme occurring in calf eye‐lens tissue. The product of the enzymatic reaction was exclusively α‐MSH. Partial sequences derived from the N‐terminus were less rapidly acetylated or not at all, depending on their chain length. The enzyme, therefore, appears to direct its activity to free N‐terminal α‐amino groups of peptides exceeding a certain critical chain length. Acetylation of ‐am

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01836.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

(Formyl‐sarcosine)1‐LH‐RH (I), (acetyl‐sarcosine)1‐LH‐RH (II), (2‐pyrrolidone‐4‐carboxylic acid)1‐LH‐RH (III), (N‐methyl‐2‐pyrrolidone‐4‐carboxylic acid)1‐LH‐RH (IV, hydroxyproline1‐LH‐RH (V) and (cyclopentane‐carboxylic acid)1‐LH‐RH (VI) were synthesized by solid phase methods on a benzhydrylamine resin support. Peptides I‐IV were assayed for LH‐ and FSH‐releasing activity over a 4‐h period after subcutaneous injection into immature male rats in order to detect any prolongation of activity. The peptides were found to have the following integrated LH‐releasing activities compared with LH‐RH: I, 64%; II, 72%; III, 19%; IV, 58%. None of the peptides were found to be longer acting than LH‐RH. Peptides V

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01837.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The solid phase synthesis of porcine secretin is described. The C‐terminal residue was attached to a polymeric amino support and all the Boc‐amino acids, including Boc‐glutamine, were coupled by a modified carbodiimide method. A preliminary test synthesis showed that the couplings of several amino acids of the N‐terminal section were unsatisfactory. This problem was overcome in the main synthesis by executing all the major reactions twice. Cleavage of the peptide from the resin as well as the removal of all the side chain protecting groups was achieved with liquid HF. The product was purified by ion‐exchange chromatography on SP‐Sephadex to obtain a highly purified heptacosapeptide amide with full biologic

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1977.tb01838.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY