Properties of a CDP-diglyceride hydrolase from guinea pig brain

Enzymatic hydrolysis of the pyrophosphate bond of CDP-diglyceride (CDP-DG), previously shown to occur in bacteria, is demonstrable in mammalian tissues. Activity was enriched in a lysosomal fraction obtained from guinea pig cerebral cortex and was purified 92-fold relative to the homogenate by a combination of XM-300 ultrafiltration and DEAE-cellulose column chromatography. When incubated with CDP-dipalmitin, the purified enzyme produced stoichiometric amounts of CMP and phosphatidate. dCDP-DG served as a substrate, while ADP-DG was an inhibitor, as were 5'-AMP and 5'-dAMP. CDP-DG hydrolysis was not affected by the presence of excess amounts of CDP-choline, CDP-glycerol, sodium pyrophosphate, or cyclic 3',5'-AMP.