Characterization of Arabidopsis secretory phospholipase A2-γ cDNA and its enzymatic properties

Plant secretory phospholipases A(2) (sPLA(2)S) probably play important roles in phospholipid signaling based on the data reported from other organisms, but their functions are poorly understood because of the lack of cloned sPLA(2) genes. In this study, we cloned and characterized an Arabidopsis secretory phospholipase A(2)-gamma (AtsPLA(2)-gamma) cDNA, and examined its enzymatic properties. The recombinant protein of AtsPLA(2)-gamma showed maximal enzyme activity at pH 8.0, and required Ca2+ for activity. Moreover, AtsPLA(2)-gamma showed sn-2 position specificity but no prominent acyl preference, though it showed head group specificity to phosphatidylethanolamine rather than to phosphatidylcholine. AtsPLA(2)-gamma was found to predominate in the mature flower rather than in other tissues, and subcellular localization analysis confirmed that AtsPLA(2)-gamma is secreted into the intercellular space. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.