title: A new deoxyuridine-5'-triphosphatase in Yoshida sarcoma cells involved in deoxyuridine 5'-triphosphate metabolism.
abstract: A magnesium-independent deoxyuridine-5'-triphosphatase was found in Yoshida sarcoma cells but not in normal rat liver. The phosphatase is specific for deoxyuridine 5'-diphosphate and deoxyuridine triphosphate, and its Km for deoxyuridine triphosphate is 2.7 X 10(-7) M. The enzyme was not inhibited by fluoride and required no divalent cations. Thus it differs from known nucleotide phosphatases. Deoxyuridine monophosphokinase, which is detectable in a crude extract of normal rat liver, could not be detected in an extract of Yoshida sarcoma cells. However, with hydroxylapatite column chromatography of the extract, a deoxyuridine 5'-monophosphate kinase activity as high as that in normal rat liver was found in fractions separated from the phosphatase activity. Thus the absence of detectable deoxyuridine 5'-monophosphate kinase activity in the crude extract of Yoshida sarcoma cells is due to the presence of this nucleotide phosphatase.
mesh_terms: D000818:Animals; D003854:Deoxyribonucleotides / Q000378:metabolism; D006868:Hydrolysis; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011755:Pyrophosphatases / Q000378:metabolism*; D051381:Rats; D012517:Sarcoma, Yoshida / Q000201:enzymology*; D014500:Uracil Nucleotides / Q000378:metabolism*
chemical_list: D003854:Deoxyribonucleotides; D014500:Uracil Nucleotides; D011755:Pyrophosphatases