Kinetic study of the enantioselective hydrolysis of a meso-diester using Pig Liver Esterase

A kinetic study of the hydrolysis of the diester dimethyl cis-cyclohex-4-ene-1,2-dicarboxylate, to the (1S,2R)-monoester, catalysed by the enzyme Pig Liver Esterase (PLE) was performed. The effects of the most relevant parameters that influence the enzymatic conversion were studied, such as pH, temperature and concentration of substrate and reaction products. It was concluded that the pH at which the enzyme exhibits a maximum activity is pH 7. At 25°C PLE presents a better long-term stability and enantioselectivity than at higher temperatures, although the reaction rate is slower. The kinetic results obtained are well described by the Michaelis-Menten equation, although a slight deviation to this model was observed for low substrate concentrations. Methanol, a co-product of the enzymatic hydrolysis, was found to act as a non-competitive inhibitor of the reaction. The Michaelis-Menten parameters were determined and a comprehensive kinetic model, which already accounts for methanol inhibition, is presented. (C) 2000 Society of Chemical Industry.