an extracellular PLA1 exhibiting triacylglycerol hydrolase activity. 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. Industrial use 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. PLA1 is currently commercially unavailable because of this. Lysophospholipids can be found as surfactants in food techniques and cosmetics, and can be used in drug delivery. Current research is being applied to determine suitable growth environments for PLA1 production. In one particular study, it was found that PLA1 can be produced by S. cerevisiae and A. oryzae. In these PLA1 producing cultures, increasing the nitrogen and carbon sources can lead to increase in PLA1 yields. Discovery In the early 1900s, an observation was made, showing an accumulation of free fatty acids after incubation of pancreatic juice with phosphatidylcholine. One of the first cases of observed PLA1 activity was on 1903 when snake venom was found to alter phosphatidylcholine into lysophosphatidylcholine, which is defined as a phosphatidylcholine without one of its fatty acids. In the 1960s, it was discovered to be that enzymes catalyze this fatty acid cleavage in multiple ways, one of which is the sn-1 position. This particular reaction is catalyzed by PLA1, while the reaction at the sn-2 position is catalyzed by phospholipase A2. See also Outer membrane phospholipase A1 References Peripheral membrane proteins EC 3.1.1