Phospholipases

Phospholipases are hydrolytic enzymes cleaving ester bonds in phospholipids. Based on According to the position of the cleaved ester bond we can differentiate between five types of phospholipases: : phospholipase A1, A2, B, C, D. Thanks to phospholipases, second messengers or arachidonic acid and subsequently eicosanoids can be formed.

Phospholipase B
It acts at the sites of action of phospholipase A1 and phospholipase A2. It hydrolyzes both ester bonds in position 1 and 2 of the respective phospholipid.

Phospholipase C
It hydrolyzes the ester bond in position 3 and releases diacylglycerol (DAG) and a phosphorylated base (e.g. phosphocholine). It is used in the signaling pathways of many cells of the human body, it hydrolyzes the phospholipid phosphatidylinositol-4,5-bisphosphate into two second messengers – diacylglycerol and inositol-1,4,5-trisphosphate.

Phospholipase D
It catalyzes the hydrolysis of phospholipids to release phosphatidic acid and compounds that were bound to phosphate (choline, serine, ethanolamine...). Phosphatidylcholine forms phosphatidic acid and choline is released.

Related articles

 * Buněčná signalizace (czech wikiskripta)
 * Phospholipids
 * Second messengers