Accession Number : AD0689428

Title :   WATER INSOLUBLE DERIVATIVES OF PROTEINS WITH BIOLOGICAL ACTIVITY.

Descriptive Note : Final rept. 1 Jul 67-30 Jun 68,

Corporate Author : WEIZMANN INST OF SCIENCE REHOVOTH (ISRAEL) DEPT OF BIOPHYSICS

Personal Author(s) : Katchalski,Ephraim

Report Date : 30 JUN 1968

Pagination or Media Count : 24

Abstract : A series of compounds were prepared and their properties as substrates of Chymotrypsin were investigated. A comparison of values of kinetic parameters for the various series, led to an estimate of the effect of side-chain length (n) of the polyfunctional ester substrates (series a), on the individual rate constants of the chymotrypsin catalyzed hydrolysis of these compounds. A systematic study of the kinetic behavior of chymotrypsin, polyglutamyl chymotypsin (PGCH) and polyornithyl-polyornithylochymotrypsin (POOCH) using acetyl-L-tyrosine ethyl ester as substrate were carried out. The values of kcat for POOCH were lower and for PGCH higher as compared to the kcat calues of native chymotrypsin. The values of KM(app) for POOCH were higher by about one order of magnitude as compared to the native enzyme. The values of KM(app) for PGCH were similar to KM(app) of chymtypsin. The kinetic data was interpreted in terms of specific nearest neighbor effects of the charged side-chains on the group(s) involved in the deacylation step, and perturbation of the binding constant, Ks, in the case of POOCH. (Author)

Descriptors :   (*CHYMOTRYPSIN, REACTION KINETICS), ESTERS, HYDROLYSIS, CATALYSIS, PROTEINS, SUBSTRATES, ELECTROLYTES, ISRAEL

Subject Categories : Biochemistry
      Biology

Distribution Statement : APPROVED FOR PUBLIC RELEASE