DIFFERENCES BETWEEN PYRIMIDINE NUCLEOSIDE MONOPHOSPHATE KINASE FROM RAT NOVIKOFF ASCITES HEPATOMA AND RAT-LIVER

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (7) , 2312-2316
Abstract
Pyrimidine nucleoside monophosphate kinase [dCMP:ATP phosphotransferase, EC 2.7.4.14] was purified from rat Novikoff ascites hepatoma and rat liver, each to a single major band appearing on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Differences exist in regard to efficiency and regulation of enzymatic activities. The Km values of the tumor kinase for CMP (0.0053 .+-. 0.0008 mM) and dCMP (0.715 .+-. 0.068 mM) are approximately 1/4 the Km values of the rat liver kinase for CMP (0.030 .+-. 0.007 mM) and dCMP (2.77 .+-. 0.39 mM). The tumor dCMP kinase exhibits a lower Km for ATP (0.134 .+-. 0.008 mM) than rat liver kinase (0.68 .+-. 0.09 mM). The dCMP:CMP kinase activity ratio for the tumor enzyme is 1.12, while that for the rat liver enzyme is 0.45. The UMP:CMP kinase activity ratio for the tumor enzyme is 1.93, while that for rat liver enzyme is 2.68.