New Inhibitors of Enzymatic Proteolysis ∗ †

Abstract

Summary

(1) The hydrolysis of egg-white by pepsin, trypsin, and chymotrypsin was inhibited by aniline, arginine, creatine, diethyl-dithiocarbamate, ethylenediamine, guanidine, lysine, o-phenylenediamine, pyrophosphate, sulfanilic acid, and a variety of carbonyl group reagents. The hydrolysis of this substrate by trypsin and chymotrypsin was also inhibited by N,N,N′,N′-tetracarboxymethyl-ethylenediamine. (2) The peptic hydrolysis of casein was inhibited by guanidine, and by several carbonyl group reagents. The hydrolysis of casein by trypsin and chymotrypsin was not inhibited by arginine, ethylenediamine, guanidine, lysine, and sulfanilic acid. (3) The hydrolysis of carbobenzoxy-L-glutamyl-L-tyrosine by pepsin was not influenced by hydrazine, but was slightly (9-14%) inhibited by guanidine. The effect of trypsin on benzoyl-L-arginineamide was inhibited by arginine, guanidine, and lysine, but not by creatine, hydrazine, hydroxylamine, phenyl-hydrazine, and Versene. (4) Dialysis and re-crystallization experiments with enzyme-inhibitor mixtures led to the recovery of fully active enzymes. The experimental evidence suggests that not the enzymes but the substrates are influenced by the inhibitors listed above, in such a manner that they become more resistant to enzymatic attack.