Molecular properties of enzymes involved in diacylglycerol and phosphatidate metabolism.

Diacylglycerol and phosphatidate serve as key lipid intermediates of glycerolipid biosynthesis and also as the second messengers liberated in signal-stimulated cells. The molecular properties of enzymes involved in the metabolic processing of the two lipids are largely unknown. We have revealed by cDNA cloning the presence of a novel enzyme family of diacylglycerol kinase (DGK) having unique structural characteristics. Furthermore, we recently identified the plasma membrane-bound phosphatidate phosphatase (PAP) as a 35 kDa glycoprotein. Detailed studies on the two enzymes would contribute to understanding the molecular mechanisms underlying the control of both glycerolipid biosynthesis and signal transduction.