Accession Number : AD0616081

Title :   POSTULATED CHEMICAL BASIS FOR OBSERVED DIFFERENCES IN THE ENZYMATIC BEHAVIOUR OF CHYMOTRYPSIN AND TRYPSIN,

Corporate Author : COLUMBIA UNIV NEW YORK COLL OF PHYSICIANS AND SURGEONS

Personal Author(s) : Erlanger,Bernard F. ; Cohen,William ; vratsanos,Spyros M. ; Castleman,Harriet ; cooper,A. G.

Report Date : 1964

Pagination or Media Count : 10

Abstract : The following differences between chymotrypsin and trypsin have been found: (a) Hydroxylamine can completely reactivate DEP-trypsin but not DEP-chymotrypsin. Reaction with the latter leads to the formation of some MEP-chymotrypsin which cannot be converted to active enzyme; (b) MEP-trypsin apparently can result from the reaction of DEP-trypsin with hydroxylamine only if ethylamine or cyclopropylamine is present; (c) ethylamine and cyclopropylamine can accelerate the tryptic hydrolysis of AGEE but have no effect on its chymotryptic hydrolysis; (d) the tryptic hydrolysis of specific substrates is subject to substrate activation. The hydrolysis of specific substrates by chymotrypsin is not activated by substrates, nor is it affected by ethyl or cyclopropylamine; (e) the curve relating pH to the rate of reaction of alpha-chymotrypsin with diphenylcarbamyl chloride has a maximum at pH 7.8. That of trypsin with diphenylcarbamyl chloride is essentially 'S'-shaped up to pH 9.0-9.5. The foregoing findings agree with the hypothesis that chymotrypsin has an additional general acid at its active centre. (Author)

Descriptors :   (*CHYMOTRYPSIN, BIOCHEMISTRY), (*TRYPSIN, BIOCHEMISTRY), ENZYMES, ORGANIC PHOSPHORUS COMPOUNDS, MOLECULAR STRUCTURE, AMINES, HYDROLYSIS, PH FACTOR

Distribution Statement : APPROVED FOR PUBLIC RELEASE