Diacylglycerol potentiates phospholipase attack upon phospholipid bilayers: possible connection with cell stimulation

Many phospholipases of the A or C types show a very limited ability to hydrolyse phospholipids such as phosphatidylcholine or phosphatidylinositol which adopt a bilayer form when hydrated. The addition of unsaturated 1,2 or 1,3 diacylglycerols to such substances produces a marked stimulation of the attack. In contrast, the hydrolysis of phosphatidylethanolamine, which normally exists in the hexagonal II structure, is not stimulated by diacylglycerol. It is suggested that the liberation of diacylglycerol which often occurs during cell stimulation, may play a part in activating the associated cascade of phospholipid reactions.