Hydrolyzes the sn-1 acylester bond of phospholipids. Phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid can be used as substrates. Weak activity with lysophosphatidylcholine and no activity with tripalmitoylglycerol and cholesteryl oleate. Seems to have a preference for unsaturated fatty acids at the sn-1 position. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 2-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) Optimum pH is 6.0-6.5. Optimum temperature is 60 to 65 degrees Celsius. Unaffected by calcium. Belongs to the AB hydrolase superfamily. Lipase family.