Kinetics of α-chymotrypsin action. III. Mechanisms of inhibition

Publisher Website
Google Scholar
Abstract
An experimental study was made of the α-chymotrypsin-catalyzed hydrolysis of N-acetyl-l-tyrosine ethyl ester, inhibited by indole and phenol. Indole inhibits noncompetitively, and analysis of the behavior shows that it binds to the enzyme and the acyl enzyme but not to the Michaelis complex; by binding to the acyl enzyme, it blocks deacylation. Phenol exhibits competitive behavior, two molecules of phenol being bound to the free enzyme in a forced-order sequence. It is concluded from the kinetics that there is either no binding of phenol to the acyl enzyme, or binding which does not affect the rate of deacylation. A general mechanism of inhibition is shown, to explain in a quantitative manner these and other inhibition results.
Keywords