Phospholipase A₂ (PLA₂, EC 3.1.1.4) cleaves the sn-2 fatty acid of phospholipids, primarily phosphatidylcholine, to generate lysophosphatidylcholine and arachidonic acid. Most commonly-used inhibitors (e.g. bromoenol lactone, arachidonyl trifluoromethyl ketone or methyl arachidonyl fluorophosphonate) are either non-selective within the family of phospholipase A₂ enzymes or have activity against other eicosanoid-metabolising enzymes.

Secreted or extracellular forms: sPLA₂-1B, sPLA₂-2A, sPLA₂-2D, sPLA₂-2E, sPLA₂-2F, sPLA₂-3, sPLA₂-10 and sPLA₂-12A

Cytosolic, calcium-dependent forms: cPLA₂-4A, cPLA₂-4B, cPLA₂-4C, cPLA₂-4D, cPLA₂-4E and cPLA₂-4F

Other forms: PLA₂-G5, iPLA₂-G6, PLA₂-G7 and PAFAH2 (platelet-activating factor acetylhydrolase 2)

The sequence of PLA₂-2C suggests a lack of catalytic activity, while PLA₂-12B (GXIIB, GXIII sPLA₂-like) appears to be catalytically inactive [7]. A further fragment has been identified with sequence similarities to Group II PLA₂ members. Otoconin 90 (OC90) shows sequence homology to PLA₂-G10.

A binding protein for secretory phospholipase A₂ has been identified which shows modest selectivity for sPLA₂-1B over sPLA₂-2A, and also binds snake toxin phospholipase A₂ [1]. The binding protein appears to have clearance function for circulating secretory phospholipase A₂, as well as signalling functions, and is a candidate antigen for idiopathic membraneous nephropathy [2].

PLA₂-G7 and PAFAH2 also express platelet-activating factor acetylhydrolase activity (EC 3.1.1.47).

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