A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D, distinguished by the type of reaction which they catalyze:
- Phospholipase A
- 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. Phospholipase Cs 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.
Phospholipase A2 acts on the intact lecithin molecule and hydrolyses 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 and viper snakes.
- Tappia, Paramjit S. & Dhalla, Naranjan S. (Editors): Phospholipases in Health and Disease. Springer, 2014. ISBN 978-1-4939-0463-1 [Print]; ISBN 978-1-4939-0464-8 [eBook]
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