title: Partial purification of deoxyuridine triphosphate nucleotidohydrolase and its effect on DNA synthesis in isolated HeLa cell nuclei.
abstract: Deoxyuridine triphosphate nucleotidohydrolase (EC 3.6.U.23) has been partially purified from HeLa S3 cells, and found to have an apparent molecular weight of 50--55 000 by gel filtration under non-denaturing conditions. The enzyme is specific for the hydrolysis of dUTP, requires Mg2+ and is inhibited by EDTA. The apparent Km for dUTP is 0.1 microM. Isolated HeLa cell nuclei were treated with dUTPase before pulse-labelling with [3H]dTTP which also had been pretreated with dUTPase. This pretreatment changed neither the total amount nor the size of the primary DNA pieces. A role for dUTP incorporation in their genesis can therefore be excluded and these primary DNA pieces are considered to be true intermediates in discontinuous DNA replication.
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis*; D004261:DNA Replication; D003856:Deoxyuracil Nucleotides; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011755:Pyrophosphatases / Q000302:isolation & purification* / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D003856:Deoxyuracil Nucleotides; D004247:DNA; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase