Staphylococcus haemolyticus lipase: high-level expression in Escherichia coli and activation of nonionic detergent

Abstract

A high level of Staphylococcus haemolyticus L62 lipase was expressed in an Escherichia coli transformant. The expressed lipase activity in the cell-free extract was 70,800 U/l, which corresponded to 30% of the total cellular proteins. Pre-mixing of the L62 lipase with some nonionic detergents enhanced its hydrolytic activity towards olive oil: Tween detergents activated the L62 lipase by 3 fold. Gel filtration chromatography of the Tween-80-L62 lipase mixture demonstrated a polymerized complex (~180 kDa) formed exclusively between Tween-80 and the L62 lipase. The lipase enzyme in the complex showed a higher specific activity towards most triacylglycerols than the intact L62 lipase. The activity enhancement towards each substrate was quite different depending on the acyl chain lengththe activity towards tributyrin, trilinolein, and trilinolenin was much more enhanced than that towards the medium and the long-chain saturated triglycerides.ope