Isolation and characterization of the extracellular lipase of Acinetobacter calcoaceticus 69 V.

The extracellular lipase of Acinetobacter calcoaceticus 69 V was purified by hydrophobic interaction chromatography to homogeneity as suggested by gel electrophoretic analysis. The lipase existed as a high molecular complex of about 300 kDa, with a subunit molecular weight of 30.5 kDa being obtained by SDS-PAGE. The hydrodynamic molecular radius obtained by gel electrophoresis was 3.27 nm. The lipase had an isoelectric point of 5.5 and was stimulated by additions of deoxycholate. The activation energy for the hydrolysis of p-nitrophenyl palmitate was 39.9 kJ mol-1. Tri-, di- and monoacylglycerols were hydrolyzed. Hg2+ and p-hydroxymercuribenzoate inhibited the enzyme activity at very low concentrations. One sulfhydryl group was found per molecule of lipase.