title: An exonuclease activity associated with DNA polymerase I of Micrococcus radiodurans.
abstract: An exonuclease activity is associated with one of three DNA polymerase in Micrococcus radiodurans. The nuclease activity co-sedimented with its DNA polymerase I of this bacterium on glycerol gradient centrifugation. Both activities show the same optimum pH and heat-inactivation kinetics. This nuclease hydrolyzes preferentially double-stranded DNA in an exonucleolytic manner from both ends of the duplex DNA. The products of hydrolysis are mostly deoxyribonucleoside 5'-monophosphate and no nucleosides are released into the acid-soluble fraction. Di- or other oligonucleotides are also produced but their relative amounts are constant during the time of incubation. The exonuclease activity requires Mg2+ and is inhibited by high concentrations of KCl as is DNA polymerase I of M. radiodurans.
mesh_terms: D004256:DNA Polymerase I / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D005092:Exonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008837:Micrococcus / Q000201:enzymology*; D011067:Poly dA-dT / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D013942:Thymine Nucleotides / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D013942:Thymine Nucleotides; D011067:Poly dA-dT; D008345:Manganese; D011189:Potassium Chloride; D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase; D003851:Deoxyribonucleases; D005092:Exonucleases; D008274:Magnesium