Phospholipase

{{Short description|Class of enzymes that cleave phospholipids}}

Image:Phospholipases2.svg.]]

A phospholipase is an enzyme that hydrolyzes phospholipids{{DorlandsDict|six/000081983|phospholipase}} 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.{{cite journal | vauthors=Yu JE, Han SY, Wolfson B, Zhou Q | title=The role of endothelial lipase in lipid metabolism, inflammation, and cancer| journal= Histology and Histopathology | volume=33 | issue=1 | pages=1–10 | year=2018 | doi=10.14670/HH-11-905 | pmc =5858721 | pmid = 28540715 }}

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.D. M. Vasudevan & S. Sreekumari, Textbook of Biochemistry (5th ed.)