Physicochemical property modification strategies based on enzyme substrate specificities III: carboxypeptidase A hydrolysis of aspirin derivatives.

The aspirin derivatives aspirin phenylalanine and aspirin phenyllactic acid were studied as substrates for carboxypeptidase A. The phenyllactic acid derivative (an ester) was the best substrate but showed considerable product inhibition. The kinetic parameters for both substrates were in the range expected on the basis of other known substrates. The results indicate that the acylamide substituent (drug) has only a small effect on the enzyme kinetic parameters. Consequently, carboxypeptidase A may serve as a reconversion site for many drug derivatives.