Isolation and characterization of phospholipase a from sea snake, Laticauda semifasciata venom

Abstract Phospholipase A has been purified from venom of the sea snake Laticauda semifasciata by chromatography on CM-cellulose followed by chromatography on DEAE-cellulose. The preparation, which was shown to be homogeneous by zonal electrophoresis, ultracentrifugation, isoelectric focusing, and gel filtration, had a specific activity seven times that of crude venom. By using ovolecithin of known composition in the 1 and 2 positions, the enzyme was shown to be specific for the 2 position, liberating mainly unsaturated fatty acids. The molecular weight of the enzyme, determined by both Sephadex gel filtration and by a combination of s and D from ultracentrifugation is 11,000. Of several phospholipids tested, only phosphatidyl choline was hydrolyzed. The enzyme was activated by Ca 2+ and to a lesser degree by Mg 2+ . The cations Zn 2+ and Cd 2+ both completely inhibited the enzyme, even in the presence of Ca 2+ . The preparation was most active at pH 8.0, and at temperatures between 35 and 40 °. The enzyme exhibited hemolytic activity which was greatly intensified by the addition of lecithin. The purified phospholipase A was nontoxic, nonhemorrhagic, and exhibited only slight myolytic activity.