Phosphatidate cytidyltransferase

Biosynthesis of phosphatidylinositols and phosphatidylglycerols. Enzymes (1) glycerol kinase (2) acyltransferases (3) phosphatidate cytidyltransferase (4) CDP-diacylglycerol inositol phosphatidate transferase (5) CDP-diacylglycerol in-glycerol-3-phosphate phosphatidate transferase (6) phosphatase (7) phosphatidylglycerol CDP-diacylglycerol phosphatidate transferase. 

Douce (1968) and Sumida and Mudd (1968) simultaneously reported the biosynthesis of CDP-DG (phosphatidate cytidyltransferase, E.C. 2.7.7.41) by particulate preparations from cauliflower inflorescence. Extensions of these preliminary reports characterized the enzymatic activity. Sumida and Mudd (1970b) used a 20,000-g particulate fraction whose activity was increased either by freezing and thawing or exposure to 0.02% Triton X-100. The competing activity of CTP hydrolysis could be prevented by fluoride, but even then the reaction quickly departed from linearity. The metal ion requirement was best satisfied by Mn + with a sharp optimum at 1 mM, but one-fourth of the maximum rate could be achieved with Mg at 30 mM. The pH optimum was found to be 5.6. 

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