Kinetics and mechanism of catalysis by proteolytic enzymes: The kinetics of hydrolysis of derivatives of l-lysine and S-(beta-aminoethyl)-l-cysteine(thialysine)by bovine trypsin.

1. Several esters of the alpha-N-toluene-p-sulphonyl and N-benzoyl derivatives of l-lysine and S-(beta-aminoethyl)-l-cysteine have been synthesized. 2. The kinetics of hydrolysis of the esters by bovine trypsin have been compared. Values of k(0) are similar for corresponding derivatives of the isosteric amino acids and deacylation of an acyl-enzyme appears to be rate-determining in each case. There are, however, some quantitative kinetic differences between the various series of substrates.