MULTIFUNCTIONAL MICELLAR CATALYSIS AS A MODEL OF ENZYME ACTION.

Article abstract of DOI:10.1021/ja00343a029

The rate constants of both the acylation and deacylation processes in the hydrolyses of p-nitrophenyl acetate (PNPA) and hexanoate (PNPH) by imidazole catalysts (1) in the presence of surfactant micelles (2) have been directly determined under single turnover conditions at pH 7. 30 in 0. 02 M phosphate buffer and 25 degree C. The major course of catalysts was the acylation followed by deacylation at the imidazole group. The kinetic analysis suggests that a multifunctional mode of action is involved in the catalystic ester hydrolysis; the acylation and deacylation rates are accelerated by carboxylate ion in the catalyst and by surfactant hydroxyl group, respectively.