title: Characterization of pyrimidine nucleoside monophosphokinase in normal and malignant tissues.
abstract: It was found that there are two kinds of pyrimidine nucleoside, monophosphokinase deoxythymidine 5'-monophosphate-deoxyuridine 5'-monophosphate (dTMP-dUMP) kinase and cytidine 5'-monophosphate-deoxycytidine 5'-monophosphate-uridine 5'-monophosphate-doexyuridine 5'-monophosphate (CMP-dCMP-UMP-dUMP) kinase, and their molecular weights were calculated to be 46,000 and 26,000, respectively, by gel filtration. dTMP-dUMP kinase phosphorylated dTMP with a Km of 3.1 X 10(-5)M and dUMP with a Km of 7.7 X 10(-4) M. dTMP phosphorylation catalyzed by dTMP-dUMP kinase was inhibited competively by dUMP with a Ki of 2.0 X 10(-3) M. Similarly, phosphorylation of dUMP by this enzyme was inhibited competively by dTMP with a Ki of 2.5 X 10 (-5) M. CMP-dCMP-UMP-dUMP kinase of Yoshida sarcoma phosphorylated dUMP with a Km of 3.1 X 10(-3) M and dCMP with a Km of 7.1 X 10 (-4) M, but it did not phosphorylate dTMP. Phosphorylation of dUMP BY CMP-dCMP-UMP-dUMP kinase was inhibited competitively by DCMP and dTMP with Ki's of 6.9 X 10(-4) and 3.0 X 10(-3) M, respectively, and phosphorylation of dCMP was inhibited completely by dUMP a Ki of 2.2 X 10(-3) M. Relative Vmax activity of this enzyme was 345 nmoles/mg protein with dCMP and 127 nmoles/mg protein with dUMP.
mesh_terms: D000818:Animals; D003568:Cytidine Monophosphate / Q000378:metabolism; D003843:Deoxycytidine Monophosphate / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D008970:Molecular Weight; D009703:Nucleoside-Phosphate Kinase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism*; D011742:Pyrimidine Nucleotides / Q000378:metabolism*; D051381:Rats; D012517:Sarcoma, Yoshida / Q000201:enzymology*; D013938:Thymidine Monophosphate / Q000378:metabolism; D014500:Uracil Nucleotides
chemical_list: D003854:Deoxyribonucleotides; D011742:Pyrimidine Nucleotides; D014500:Uracil Nucleotides; D003843:Deoxycytidine Monophosphate; D013938:Thymidine Monophosphate; D010770:Phosphotransferases; C023276:uridine monophosphate kinase; D009703:Nucleoside-Phosphate Kinase; D003568:Cytidine Monophosphate