Characterization of phospholipase A2 from the pyloric ceca of two species of starfish, Coscinasterias acutispina and Plazaster borealis

Abstract Phospholipase A (PLA) activities in the pyloric ceca and viscera from seven species of marine invertebrates (four starfish, one sea urchin, and two shellfish) were determined. Relatively high PLA specific activities were found in the pyloric ceca of two species of starfish ( Coscinasterias acutispina and Plazaster borealis ). Phospholipase A 2 s (PLA 2 s) were partially purified from the pyloric ceca of the starfish, C. acutispina PLA 2 (C-PLA 2 ) and P. borealis PLA 2 (P-PLA 2 ). The C-PLA 2 and P-PLA 2 mainly released oleic acid from 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphocholine. Temperature optima of the C-PLA 2 and P-PLA 2 were at around 60 °C and 50 °C, respectively, and pH optima of the C-PLA 2 and P-PLA 2 were both at around pH 10.0. The activities of the C-PLA 2 and P-PLA 2 were enhanced by sodium deoxycholate and 1 mM or higher concentration of Ca 2+ . The C-PLA 2 and P-PLA 2 did not show the fatty acid specificity for hydrolysis of phosphatidylcholine. Unlike porcine pancreatic PLA 2 , the C-PLA 2 and P-PLA 2 hydrolyzed phosphatidylcholine more effectively than phosphatidylethanolamine.