Purification, characterization and kinetic properties of the rabbit gastric lipase

Rabbit gastric lipase was purified from an acetonic powder of rabbit stomach fundus. 25 mg of pure rabbit gastric lipase (glycerol ester hydrolase, EC 3.1.1.3) was obtained from 30 rabbit stomachs after ammonium sulfate fractionation, Sephadex G-100 gel filtration and cation exchange (mono S column) using a fast protein liquid chromatography (FPLC) system. The pure enzyme obtained was resistant to acidic pH conditions, and had specific activities of 1200, 850 and 280 U/mg, using, respectively, short- (tributyroylglycerol (TC4)), medium- (trioctanoyl- to tridecanoylglycerol (TC8-TC10)) and long-chain (soybean oil) triacylglycerols. The amino-acid composition was determined, and the first 30 N-terminal amino-acid residues were sequenced. Interfacial denaturation and catalytic properties on triacylglycerol emulsions were studied. Rabbit gastric lipase turned out to be structurally and kinetically very similar to human gastric lipase.