An active-site titrant for chymotrypsin, and evidence that azapeptide esters are less susceptible to nucleophilic attack than ordinary esters

Article abstract of DOI:10.1016/0960-894X(96)00308-3

The p-nitrophenyl ester of N-methoxycarbonylazaphenylalanine reacts with chymotrypsin in 1:1 stoichiometry, and the enzyme concentration can be quantified from the absorbance of the p-nitrophenolate produced in the reaction. This azapeptide does not decom