Purification and properties of a novel lipase from Staphylococcus aureus 226

A novel lipase of Staphylococcus aureus 226 was purified by ammonium sulfate precipitation followed by successive chromatographies on hydroxylapatite, Sephadex G-200 and G-150. This method gave 385-fold purification of the enzyme from the culture medium in a yield of 25%. The purified enzyme appeared homogeneous on polyacrylamide gel electrophoresis and isoelectric focusing. The purified lipase hydrolyzed all the triacylglycerols and 1-monoacylglycerols tested, showing maximal activity with trilaurin and 1-monoolein. Furthermore, 2-monoolein was also found to be one of the best substrates for the lipase. The optimum temperature of the purified enzyme was 60 degrees C with triolein. The molecular weight of the enzyme was reduced in the presence of sodium deoxycholate and was estimated as 34,000 by gel filtration and its isoelectric point as 9.7. Mg2+ and Ca2+ ions enhanced the enzymatic reaction, whereas Mn2+ ions were inhibitory. p-Chloromercuribenzoate, iodoacetamide, and N-ethylmaleimide did not inhibit the enzyme.