Methods for measuring the activity and expression of phospholipase D

Phospholipase D (PLD) was de ned in 1947 by Hanahan and Chaikoff in carrot extracts as a phospholipid-speci c phosphodiesterase that hydrolyzed phosphatidylcholine (PtdCho) to generate phosphatidic acid (PtdOH) and choline [1,2]. PLD activity was thought to be absent in animal tissues, in retrospect, due to the abundant levels of inhibitors that are found in crude extracts, until Saito and Kanfer demonstrated 30 years later that rat brain preparations could release choline and ethanolamine from PtdCho and phosphatidylethanolamine (PtdEtn), respectively [3]. PLD is now known to be present in all organisms [4].