Phospholipase
A phospholipase is an enzyme that hydrolyzes phospholipids<ref>Template:DorlandsDict</ref> into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C, and D, which are distinguished by the type of reaction which they catalyze:
- Phospholipase A
- Phospholipase A1 – cleaves the sn-1 acyl chain (where sn refers to stereospecific numbering).
- Phospholipase A2 – cleaves the sn-2 acyl chain, releasing arachidonic acid.
- Phospholipase B – cleaves both sn-1 and sn-2 acyl chains; this enzyme is also known as a lysophospholipase.
- Phospholipase C – cleaves before the phosphate, releasing diacylglycerol and a phosphate-containing head group. PLCs play a central role in signal transduction, releasing the second messenger inositol triphosphate.
- Phospholipase D – cleaves after the phosphate, releasing phosphatidic acid and an alcohol.
Types C and D are considered phosphodiesterases.
Endothelial lipase is primarily a phospholipase.<ref name="pmid28540715">Template:Cite journal</ref>
Phospholipase A2 acts on the intact lecithin molecule and hydrolyzes the fatty acid esterified to the second carbon atom. The resulting products are lysolecithin and a fatty acid. Phospholipase A2 is an enzyme present in the venom of bees, blennies and viper snakes.<ref>D. M. Vasudevan & S. Sreekumari, Textbook of Biochemistry (5th ed.)</ref>
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Further readingEdit
- Tappia, Paramjit S. & Dhalla, Naranjan S. (Editors): Phospholipases in Health and Disease. Springer, 2014. Template:ISBN [Print]; Template:ISBN [eBook]