Purification and partial characterization of nonspecific lipase from rat pancreas

Nonspecific lipase (also referred to as micelle lipase and secondary ester hydrolase) has been purified to electrophoretic homogeneity starting from acetone powder of rat pancreas. The purified enzyme is found to have a molecular weight (gel filtration) of 64 000 +/- 2000, and an equivalent weight (titration with E-600) of 65 000. Nonspecific lipase is seen to be very sensitive to inhibition by organophosphates but resistant to quinine. Evidence for the presence of sulfhydryl and imidazole groups essential for activity is presented, and some observations on substrate specificity are made. The purified enzyme appears to lack phosphate groups and lipids, and is unstable under conditions of low ionic strength and/or exposure to 2-mercaptoethanol.