MEASUREMENT OF PHOSPHOLIPASE-D ACTIVITY

Phosphodiesteric cleavage of phosphatidylcholine by members of a growi ng family of phospholipases D produces choline and phosphatidic acid. These enzymes can also catalyse a transphosphatidylation reaction in w hich the aliphatic chain of a primary alcohol is transferred to the ph osphatidyl moiety of the phosphatidic acid product. PLD enzymes are fo und in a variety of organisms including bacteria, yeast, plants, and v ertebrates. In mammalian systems, biochemical and cell biological appr oaches have identified phosphatidic acid as a mediator (or progenitor of mediators) that play important roles in the transduction of extrace llular signals. Phosphatidic acid or its metabolites may be regulators of key cellular processes such as the control of intracellular protei n trafficking, secretion, and alterations in cell morphology and motil ity. This review discusses methods for the determination of PLD activi ty both in vitro and in intact cells. (C) 1997 Academic Press.