Purification and Properties of Lipase from Tilapia Stomach —Digestive Enzyme of Tilapia-VII—

¹Department of Brewing and Fermentation, Junior College of Tokyo University of Agriculture, Tokyo, 156-8502, ²Department of Applied Biology and Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo, 156-8502, Japan

Lipase of the stomach of Tilapia nilotica was purified by ammonium sulfate precipitation, followed by chromatofocusing (Polyexchanger PBE 94), and gel filtration (Sephadex G-100). The lipase was found to be a single band when examined by electrophoresis.

The specific activity of the purified enzyme was 19 times higher than that of the crude extract.

The lipase had a molecular weight of 54,000, showed the optimum activity at pH6.5 and 40°C, and was stable at pH5.0-7.0 and below 50°C. The Km of the enzyme for olive oil was calculated to be 0.6mM. Its activity was inhibited by Cu^2＋, Cd^2＋, Pb^2＋, Hg^2＋, Ni^2＋, PCMB, and EDTA.

This enzyme hydrolyzed triacylglycerol more than diacylglycerol and monoacylglycerol. The enzyme hydrolyzed soybean oil well.

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