Phospholipase

Phospholipase cleavage sites. An enzyme that displays both PLA₁ and PLA₂ activities is called a phospholipase B.

A phospholipase is an enzyme that hydrolyzes phospholipids^[1] 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.^[2]

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.^[3]

See also

• Patatin-like phospholipase
• Infantile neuroaxonal dystrophy

References

1. "phospholipase" at Dorland's Medical Dictionary
2. Yu JE, Han SY, Wolfson B, Zhou Q (2018). "The role of endothelial lipase in lipid metabolism, inflammation, and cancer". Histology and Histopathology. 33 (1): 1–10. doi:10.14670/HH-11-905. PMC 5858721. PMID 28540715.
3. D. M. Vasudevan & S. Sreekumari, Textbook of Biochemistry (5th ed.)

Further reading

• 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]

External links

• Phospholipases at the U.S. National Library of Medicine Medical Subject Headings (MeSH)