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
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
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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
SymbolPhospholip_A2_1
PfamPF00068
InterProIPR001211
PROSITEPDOC00109
SCOP21bbc / SCOPe / SUPFAM
OPM superfamily82
OPM protein1g4i
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

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]

  1. ^ 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.
  2. ^ 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.
  3. ^ 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.
  4. ^ Cox M, Nelson DR, Lehninger AL (2005). Lehninger principles of biochemistry (4th ed.). San Francisco: W.H. Freeman. ISBN 0-7167-4339-6.