Purification and some properties of rat spleen phospholipase A2

Intracellular phospholipase A2 was purified to homogeneity from rat spleen. The enzyme was efficiently concentrated by precipitation with trichloroacetic acid and purified by sequential use of column chromatographies on DEAE-Sepharose, octyl-Sepharose and Bio-Gel P-30. The positional specificity of the enzyme for an acylester bond at the sn-2-position of phospholipids was established. The purified enzyme has a pH optimum ranging from 8.0 to 10.5 and the molecular weight of the enzyme was estimated to be 14,700-14,800 by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by gel filtration with a TSK-GEL G 2000 SW column. The purified enzyme requires Ca2+ for activity. The activity was not enhanced by the presence of purified calmodulin.