title: Inhibition of DNA polymerase-alpha and -beta of calf thymus by 1-beta-D-arabinofuranosylcytosine-5'-triphosphate.
abstract: 1-beta-D-Arabinofuranosylcytosine 5'-triphosphate (araCTP), an active form of a inhibitor of DNA replication, 1-beta-D-arabinofuranosylcytosine (araC) was tested for its inhibitory action on the DNA polymerase-alpha and -beta (EC 2.7.7.7) purified from calf thymus. The reaction of DNA polymerase-alpha was shown to be more sensitive to the inhibition by araCTP than that of DNA polymerase-beta. The mode of the inhibition by araCTP was competitive to dCTP in the reaction catalysed by either DNA polymerase-alpha or -beta. The Ki value of DNA polymerase-beta for araCTP was 32 micron; eight times higher than that of DNA polymerase-alpha (4 micron) for this inhibition.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D003561:Cytarabine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors*; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors*; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D019384:Nucleic Acid Synthesis Inhibitors; D013329:Structure-Activity Relationship; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D019384:Nucleic Acid Synthesis Inhibitors; D003561:Cytarabine; D004256:DNA Polymerase I; D004257:DNA Polymerase II