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Phospholipase A2
| phospholipase A2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Phospholipase cleavage sites. Note that an enzyme that displays both PLA1 and PLA2 activities is called a phospholipase B. | |||||||||
| Identifiers | |||||||||
| EC no. | 3.1.1.4 | ||||||||
| CAS no. | 9001-84-7 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
| Phospholipase A2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Bee venom phospholipase A2 sPLA2. Middle plane of the lipid bilayer - black dots. Boundary of the hydrocarbon core region - red dots (extracellular side). Layer of lipid phosphates - yellow dots. | |||||||||
| Identifiers | |||||||||
| Symbol | Phospholip_A2_1 | ||||||||
| Pfam | PF00068 | ||||||||
| InterPro | IPR001211 | ||||||||
| PROSITE | PDOC00109 | ||||||||
| SCOP2 | 1bbc / SCOPe / SUPFAM | ||||||||
| OPM superfamily | 82 | ||||||||
| OPM protein | 1g4i | ||||||||
| |||||||||
The enzyme phospholipase A2 (EC 3.1.1.4, PLA2, systematic name phosphatidylcholine 2-acylhydrolase) catalyses the cleavage of fatty acids in position 2 of phospholipids, hydrolyzing the bond between the second fatty acid "tail" and the glycerol molecule:
- phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate
This particular phospholipase specifically recognizes the sn2 acyl bond of phospholipids and catalytically hydrolyzes the bond, releasing arachidonic acid and lysophosphatidyl choline, a precursor of lysophosphatidic acid. Upon downstream modification by cyclooxygenases or lipoxygenases, arachidonic acid is modified into active compounds called eicosanoids. Eicosanoids include prostaglandins and leukotrienes, which are categorized as anti-inflammatory and inflammatory mediators.[1]
PLA2 enzymes are commonly found in mammalian tissues as well as arachnid, insect, and snake venom.[2] Venom from bees is largely composed of melittin, which is a stimulant of PLA2. Due to the increased presence and activity of PLA2 resulting from a snake or insect bite, arachidonic acid is released from the phospholipid membrane disproportionately. As a result, inflammation and pain occur at the site.[3] There are also prokaryotic A2 phospholipases.
Additional types of phospholipases include phospholipase A1, phospholipase B, phospholipase C, and phospholipase D.[4]
- ^ Dennis EA (May 1994). "Diversity of group types, regulation, and function of phospholipase A2". The Journal of Biological Chemistry. 269 (18): 13057–13060. doi:10.1016/S0021-9258(17)36794-7. PMID 8175726.
- ^ Nicolas JP, Lin Y, Lambeau G, Ghomashchi F, Lazdunski M, Gelb MH (March 1997). "Localization of structural elements of bee venom phospholipase A2 involved in N-type receptor binding and neurotoxicity". The Journal of Biological Chemistry. 272 (11): 7173–7181. doi:10.1074/jbc.272.11.7173. PMID 9054413.
- ^ Argiolas A, Pisano JJ (November 1983). "Facilitation of phospholipase A2 activity by mastoparans, a new class of mast cell degranulating peptides from wasp venom". The Journal of Biological Chemistry. 258 (22): 13697–13702. doi:10.1016/S0021-9258(17)43973-1. PMID 6643447.
- ^ Cox M, Nelson DR, Lehninger AL (2005). Lehninger principles of biochemistry (4th ed.). San Francisco: W.H. Freeman. ISBN 0-7167-4339-6.
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