Simple assay for glycerophospholipid hydrolase activity of postheparin plasma

An assay using radioactive substrates is described that permits rapid determinations of glycerophospholipid-hydrolyzing activity in postheparin plasma or its fractions. Optimal conditions are described for hydrolysis of phosphatidylcholine and phosphatidylethanolamine. A minimum of only 2 mul of normal postheparin plasma is used and no extraction of the reaction products is required before their separation by thin-layer chromatography. We found that after an optimal heparin dose of 60 units/kg body weight the rate of hydrolysis for diacyl glycerophosphocholine and diacyl glycerophosphoethanolamine is 1.16 mumoles/ml per hr and 22.4 mumoles/ml per hr, respectively.