title: Cytidine triphosphate: phosphatidic acid cytidyltransferase in Escherichia coli.
abstract: An enzyme has been found in particulate fractions of Escherichia coli that catalyzes the incorporation of cytidine triphosphate (CTP) into lipid in the presence of exogenous phosphatidic acid and Mg(++). The product has been identified enzymatically and by chromatography as cytidine diphosphate diglyceride. The reaction is optimal at a pH of 6.5 and Mg(++) concentration of 5-10 mm. The apparent K(m) for CTP is 7 x 10(-4)M and for phosphatidic acid, 2 x 10(-3)M. The reaction rate falls off rapidly with time and ceases entirely after 1 hr as the result of inactivation of the system by Mg(++).
mesh_terms: D003597:Cytosine Nucleotides / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D005989:Glycerides / Q000096:biosynthesis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008055:Lipids / Q000096:biosynthesis; D008274:Magnesium; D009713:Nucleotidyltransferases / Q000378:metabolism*; D010743:Phospholipids; D014316:Tritium; D014732:Vibration
chemical_list: D003597:Cytosine Nucleotides; D005989:Glycerides; D008055:Lipids; D010743:Phospholipids; D014316:Tritium; D009713:Nucleotidyltransferases; D008274:Magnesium