In particular, phospholipase A1 (PLA1) specifically catalyzes the cleavage at the sn-1 position of phospholipids, forming a fatty acid and a lysophospholipid.

[5] In addition to this, the products of the reaction catalyzed by PLA1 which are a fatty acid and a lysophospholipid are important in various biological functions such as platelet aggregation and smooth muscle contraction.

[13] In contrast, a PLA1 enzyme that is considered more selective will have a short lid and B9 domain that span 7-12 and 12-13 amino acids, respectively.

Unlike other phospholipases such as PLA2, there is much that is unknown about PLA1 due to the lack of any efficient way to purify, clone, express, and characterize this enzyme.

[8] In the early 1900s, an observation was made, showing an accumulation of free fatty acids after incubation of pancreatic juice with phosphatidylcholine.