Partial purification and characterization of lipase (EC 3.1.1.3) from Propionibacterium acnes

Abstract

Lipase from Propionibacterium acnes has been purified 4800-fold from crude culture supernatant. The purified enzyme preparation had no assayable protease, hyaluronate lyase or acid phosphatase activities. The molecular weight of the lipase was 46,770 as determined by gel filtration. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed a major protein component (mol. wt 41,190) together with two minor protein components (mol. wt 67,000 and 125,900). The lipase had a pH optimum of 6.8, was most stable in the pH range 5.0 to 6.0 and was completely inactivated after 30 min at 60 degrees C. The lipase hydrolysed trilaurin, triolein, trimyristin and tripalmitin at decreasing rates and did not exhibit phospholipase activity. Analysis of the reaction products from the hydrolysis of triolein by P. acnes lipase did not demonstrate an accumulation of 2-monoolein which suggested that the enzyme did not exhibit a positional specificity for the 1-position of the triacylglycerol. Crude lipase preparations contained an aggregated high molecular weight form of the enzyme which was eluted with the void volume from Sephadex G-200. This aggregated form was dissociated to produce the lower molecular weight lipase species by subsequent dialysis and elution from Sephadex G-200 using buffer with a higher ionic strength.