Utilization in vitro of deoxyuridine triphosphate in DNA synthesis by DNA polymerases alpha and beta from calf thymus

Abstract

DNA polymerases alpha and beta (EC 2.7.7.7.) from calf thymus could utilize dUTP as a substrate for DNA synthesis as well as DNA polymerase I of Escherichia coli. Deoxyuridylate was incorporated into DNA by replacing deoxythymidylate and supported the further elongation of DNA chains on activated DNA or on the intiated homopolymers, poly(dA) . (dT)10 and poly(rA) . (dT)10. The rate of the incorporation of deoxyuridylate into DNA varied from 50 to 160% of that of deoxythymidylate, depending on the nature of the template primers and the species of DNA polymerase used. The apparent Km values for dUTP were very similar to those for dTTP. Uracil DNA-glycosylase excised efficiently the uracil residues in products of DNA polymerase reactions with either activated calf thymus DNA or initiated homopolymers.