Phospholipase

Phospholipase is a member of a very complex group of enzymes that break down phospholipids into fatty acids and other compounds. Phospholipases are defined by the enzymatic reaction they catalyze. The classes are phospholipase A, which has members A1 and A2; phospholipase B, which can carry out the reactions of both A1 and A2; phospholipase C; and phospholipase D.

Phospholipase A₂ (PLA₂) catalyses the hydrolysis of the sn-2 position of glycerophospholipids to yield fatty acids and lysophospholipids. Phospholipase C (PLC) converts phosphatidylinositol 4,5-bisphosphate (PIP₂) to inositol 1,4,5-trisphosphate (IP₃) and diacylglycerol (DAG). DAG and IP₃ each control diverse cellular processes and are also substrates for synthesis of other important signaling molecules. PLC is thus central to many important interlocking regulatory networks. Phospholipase D (PLD) is an essential enzyme responsible for the production of the lipid second messenger phosphatidic acid (PA), which is involved in fundamental cellular processes, including membrane trafficking, actin cytoskeleton remodeling, cell proliferation and cell survival.