Transesterification reactions catalyzed by papain.

The hydrolysis of a series of esters of benzoyl-L-arginine and glycylglycine by papain has been examined in mixtures of water with various alcohols in the pH range of 5 to 6. The presence of straight chain alcohols resulted in an apparent inhibition of acid release. It was shown that this inhibition could, in part, be accounted for by papain-catalyzed transesterification reactions between the various substrates and the alcohols studied. The products of transesterification, transamidation, and hydrolysis resulting on incubation of papain with esters of glycylglycine were separated and identified, and the kinetics of their formation were examined. Ficin was found to behave similarly to papain. The present study, in conjunction with earlier reports, suggests that the ability to catalyze alcoholytic reactions may be a property of many hydrolytic enzymes.