Kinetic specificity in papain-catalysed hydrolyses
نویسندگان
چکیده
منابع مشابه
A Study of Some Thiol Ester Hydrolyses as Models for the Deacylation Step of Papain-catalysed Hydrolyses.
1. The self-catalysed hydrolyses of the thiol esters, S-hippurylthioglycollic acid and S-ethyl monothiolsuccinate, have been shown to be slower than the deacylation step for the papain-catalysed hydrolysis of hippuric esters, by a factor approx. 10(5). This difference in rate constants largely reflects a difference in activation energy, which together with other evidence drawn from the literatu...
متن کاملDirect Evidence for an Acylated Thiol as an Intermediate in Papain- and Ficin-catalysed Hydrolyses.
1. Methyl thionohippurate was prepared and shown to be a specific substrate for both papain and ficin. 2. The ultraviolet-absorption properties of the acyl-enzyme intermediate for both papain and ficin with methyl thionohippurate was that expected of an acyl-thiol. The possibility that other functional groups present in papain or ficin might be the site of acylation has been excluded. 3. The ch...
متن کاملA model to explain the pH-dependent specificity of cathepsin B-catalysed hydrolyses.
1. Three synthetic substrates of cathepsin B (EC 3.4.22.1) with various amino acid residues at the P2 position (Cbz-Phe-Arg-NH-Mec, Cbz-Arg-Arg-NH-Mec and Cbz-Cit-Arg-NH-Mec, where Cbz represents benzyloxycarbonyl and NH-Mec represents 4-methylcoumarin-7-ylamide) were used to investigate the pH-dependency of cathepsin B-catalysed hydrolyses and to obtain information on the nature of enzyme-subs...
متن کاملSpecificity of papain-catalyzed transamidation reactions.
In the experiments reported in the present communication, these studies have been extended with special reference to the specificity of the enzyme toward the dipeptide used as replacement agent. It had been suggested (1) that the value of pKz’ of a dipeptide is a determining factor in the efficiency with which it can participate in a transamidation reaction at ‘a given pH. This suggestion has b...
متن کاملKinetic solvent isotope effects on the deacylation of specific acyl-papains. Proton inventory studies on the papain-catalysed hydrolyses of specific ester substrates: analysis of possible transition state structures.
1. The hydrolyses of the p-nitrophenyl esters of N-benzyloxycarbonylglycine, alpha-N-benzyloxycarbonyl-L-lysine and N-methoxycarbonyl-L-phenylalanylglycine catalysed by papain (EC 3.4.22.2) have been studied in solvents having a variable composition of 2H2O and H2O. 2. kcat., which represents deacylation in the papain-catalysed hydrolysis of reactive esters, is some 2.3-fold less in 2H2O compar...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1971
ISSN: 0306-3283
DOI: 10.1042/bj1240107