(2R, 3S)- and (2S, 3R)-2-Benzyl-3,4-epoxybutanoic acid as highly efficient and fast acting pseudomechanism-based inactivators for carboxypeptidase a: design, asymmetric synthesis and inhibitory kinetics

Abstract

2-Benzyl-3,4-epoxybutanoic acid (BEBA) was studied as an irreversible inhibitor for the zinc-containing protease, carboxypeptidase A. Of four possible stereoisomers, those having a 2R, 3S- and a 2S, 3R-configuration inhibited carboxypeptidase A in a time-dependent manner. The latter compound that belongs to the D series is more effective with a k_inact/K_i value of 139.5 dm³ mol^–1 s^–1 than the former having a K_inact/K_i value of 53.9 dm³ mol^–1 s^–1. Partition ratios for (2R, 3S)- and (2S, 3R)-BEBA were determined as 1.01 and 0.53, respectively. The observed kinetic parameters reveal that both are highly efficient and fast acting pseudomechanism-based inactivators for carboxypeptidase A. Details of the kinetic analyses, design principles and asymmetric syntheses of these inactivators are described.