Measurement of phospholipase D activity.

Phosphodiesteric cleavage of phosphatidylcholine by members of a growing family of phospholipases D produces choline and phosphatidic acid. These enzymes can also catalyse a transphosphatidylation reaction in which the aliphatic chain of a primary alcohol is transferred to the phosphatidyl moiety of the phosphatidic acid product. PLD enzymes are found in a variety of organisms including bacteria, yeast, plants, and vertebrates. In mammalian systems, biochemical and cell biological approaches have identified phosphatidic acid as a mediator (or progenitor of mediators) that play important roles in the transduction of extracellular signals. Phosphatidic acid or its metabolites may be regulators of key cellular processes such as the control of intracellular protein trafficking, secretion, and alterations in cell morphology and motility. This review discusses methods for the determination of PLD activity both in vitro and in intact cells.