Water Insoluble Derivatives of Proteins with Biological Activity

摘要

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 chymotrypsin (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 values 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 chymotrypsin. 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)