Novel intestinal phospholipase A2: purification and some molecular characteristics

We purified to homogeneity a new phospholipase A2 from pig ileum which hydrolyzes phosphatidylglycerol at least 200 times more rapidly than phosphatidylcholine. The method involved the following steps: (1) complete delipidation of ileal homogenates by solvent extraction; (2) fractionation and partition between n-butanol and (NH4)2SO4 solution; (3) hydrophobic affinity chromatography on octyl-Sepharose; (4) adsorption chromatography on hydroxylapatite; (5) ion-exchange chromatography on carboxymethyl-Sepharose. Amino acid composition, molecular weight (15 000-16 000), N-terminal amino acid sequence to residue 48, and enzymatic activity on phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylglycerol were determined.