Abstract
In order to reveal a difference between the enzyme mechanisms of lipase and esterase, lipase-catalyzed methanolysis was compared with esterase-catalyzed methanolysis. 1) Purified pancreatic lipase and a mold, Mucor lipase were found to catalyze methanolysis of n-alkyl n-butyrates and tri-n-butyrin in heterogeneous assay system. 2) The same partitioning ratio (A/H), irrespective of the substrate leaving group, was obtained by our experiments. This indicates formation of a common intermediate during solvolysis. It is reasonable to postulate that this intermediate is an acyl enzyme. 3) Kinetic parameters for lipase and esterase were estimated and compared with each other. Acyl-esterase was more susceptible to nucleophilic attack by methanol than acyl-lipase.
