Physicochemical property modification strategies based on enzyme substrate specificities II: alpha-chymotrypsin hydrolysis of aspirin derivatives.

Three aspirin derivatives, aspirin phenylalanine ethyl ester, aspirin phenylalanine amide, and aspirin phenyllactic ethyl ester, were investigated with respect to their hydrolysis by alpha-chymotrypsin. Of the three compounds, aspirin phenylalanine ethyl ester was the best substrate, with kcat = 25 sec-1 and Km = 1.3 x 10-6 M at pH 8.0. The results for all substrates were in the range of expectation based on kinetic data for other substrates. The apparent latitude in the nature of the acrylamide substituent of alpha-chymotrypsin substrates makes this enzyme a good potential reconversion site for many drug derivatives.