Electrostatic effects in the alpha-chymotrypsin-catalyzed acyl transfer. II. Efficiency of nucleophiles bearing charged groups in various locations

We investigated the alpha-chymotrypsin-catalyzed acyl transfer to a series of glycine oligomers. It could be established that the electrostatic interactions between the carboxylate group of the nucleophiles and the S'-subsites of the enzyme fall off with the length of the nucleophile molecule. Additional negatively charged residues in the nucleophile lead to a considerable reduction of the acyl transfer efficiency. An arginine residue in P'1- or P'3-position, but not in P'2-position, makes favourable interactions with the appropriate S'-subsites of the enzyme.