Peptidyl epoxides as inhibitors of α-chymotrypsin: Remarkable change from irreversible to reversible competitive inhibitor as a consequence of the improvement of binding affinity

The replacement of the ester group in (2S,3R)-2-benzyl-3,4-epoxybutanoic acid methyl ester (1) with a N-benzoyl-2-pyrrolidylcarboxamide moiety changes the mode of inhibition for α-chymotrypsin from an active site directed inactivator to a reversible competitive inhibitor.