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. Present in intestine (at protein level). Expressed in colon, prostate, kidney, pancreas, ovary, testis, intestine, lung and pancreas. Expressed at lower level in brain, spleen and heart. In hair, it is prominently expressed in hair follicles, including the stem cell-rich bulge region. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the AB hydrolase superfamily. Lipase family. Truncated N-terminus.