Phospholipase A1 (EC 3.1.1.32; systematic name: phosphatidylcholine 1-acylhydrolase) encoded by the PLA1A gene is a phospholipase enzyme which removes the 1-acyl group:
- phosphatidylcholine + H2O ⇌ 2-acylglycerophosphocholine + a carboxylate
It is an enzyme that resides in a class of enzymes called phospholipase that hydrolyze phospholipids into fatty acids.  There are four classes, separated according to the type of reaction they catalyze.  In particular, phospholipase A1 (PLA1) specifically catalyzes the cleavage at the sn-1 position of phospholipids, forming a fatty acid and a lysophospholipid.