CDPdiacylglycerol synthase from yeast

This chapter describes the purification and properties of the CDPdiacylglycerol synthase from yeast. CDPdiacylglycerol synthase (CTP:phosphatidate cytidylyltransferase) catalyzes the conversion of phosphatidate to CDPdiacylglycerol. The phospholipid product of the reaction—CDPdiacylglycerol—is the source of the phosphatidyl moiety in the primary (phosphatidylethanolamine methylation) pathway for the synthesis of the major phospholipids in Saccharomyces cerevisiae. The main site of CDPdiacylglycerol synthase activity is the mitochondria. About 20% of CDPdiacylglycerol synthase activity is associated with microsomes, which is contributed mainly by plasma membrane-associated activity. The expression of CDPdiacylglycerol synthase is regulated by inositol alone and in combination with serine, ethanolamine, and choline. Mitochondrial-associated CDPdiacylglycerol synthase has been purified to apparent homogeneity. The major purification of the enzyme is achieved by CDPdiacylglycerol-Sepharose affinity chromatography. Binding of the enzyme to the affinity resin occurs because the CDPdiacylglycerol synthase reaction is favored in the reverse direction.