Purification and properties of phospholipase A2 isozymes from pyloric ceca of the starfish (Asterina pectinifera)

Phospholipase A 2 isozyme II (PLA 2 II), which showed different mobility on native PAGE from that of the PLA 2 isozyme I (PLA 2 I) isolated previously, was purified from pyloric ceca of the starfish (Asterina pectinifera). The PLA 2 II mainly released oleic acid from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. N-terminal amino acid sequence of the PLA 2 II was SVYQF. Temperature and pH optima of the PLA 2 II were at around 50C and pH 9.0, respectively, and the enzyme activity was enhanced by sodium deoxycholate and 1 mM or higher concentration of Ca 2+ . He PLA 2 II did not show fatty acid specificity for hydrolysis ofphosphatidylcholine (PC). Specific activity of the PLA 2 II was about 10 times higher than that of commercially available porcine pancreatic PLA 2 . The PLA 2 II hydrolyzed PC more effectively than phosphatidylethanolamine. These characteristics of the PLA 2 II were the same as those of the PLA 2 I.