Interfacial Kinetic and Binding Properties of the Complete Set of Human and Mouse Groups I, II, V, X, and XII Secreted Phospholipases A2

Expression of the full set of human and mouse groups I, II, V, X, and XII secreted phospholipases A 2 (sPLA 2 s) in Escherichia coli and insect cells has provided pure recombinant enzymes for detailed comparative interfacial kinetic and binding studies. The set of mammalian sPLA 2 s display dramatically different sensitivity to dithiothreitol. The specific activity for the hydrolysis of vesicles of differing phospholipid composition by these enzymes varies by up to 4 orders of magnitude, and yet all enzymes display similar catalytic site specificity toward phospholipids with different polar head groups. Discrimination between sn -2 polyunsaturated versus saturated fatty acyl chains is