Hydrolyzes specifically phosphatidic acid (PA) to produce 2-acyl lysophosphatidic acid (LPA; a potent bioactive lipid mediator) and fatty acid. Does not hydrolyze other phospholipids, like phosphatidylserine (PS), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) or triacylglycerol (TG). 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H(+) + hexadecanoate Inhibited by sodium vanadate. Interacts with heparin with a high affinity. May associate with lipid draft. May associate with lipid draft. Expressed in testis. Expressed exclusively at the connecting piece of the sperm. Disease susceptibility is associated with variants affecting the gene represented in this entry. Belongs to the AB hydrolase superfamily. Lipase family.