Template Specificity of Rat Mitochondrial DNA Polymerase

Biochim Biophys Acta. 1977 Dec 2;479(3):290-9. doi: 10.1016/0005-2787(77)90111-3.

Abstract

Mitochondrial DNA polymerase was purified 2300-fold over isolated mitochondria from rat liver. Template-primer specificities of this enzyme were investigated. Activated DNA was satisfactorily used as an active template-primer, but both native and denatured DNAs showed a slight activity. Synthetic polynucleotide, poly(dA) - oligo(dT)10 was found to have a high efficiency under the same condition for activated DNA. When the closed-circular, nicked and gapped Co1E1 DNAs were employed as a template-primer, the enzyme could only utilize the gapped DNA, indicating that the displacement synthesis was not catalyzed by the enzyme itself. The enzyme also copied poly(A) - oligo(dT)10 in high efficiency at pH 7.5 in the presence of MnCl2. Such RNA-directed DNA polymerase activity of the enzyme was further characterized. Cofractionated endouclease activity was completely separated from the enzyme by glycerol gradient centrifugation.

MeSH terms

  • Animals
  • DNA / metabolism
  • DNA, Circular / metabolism
  • DNA, Single-Stranded / metabolism
  • DNA-Directed DNA Polymerase / metabolism*
  • Endonucleases / metabolism
  • In Vitro Techniques
  • Mitochondria, Liver / enzymology*
  • Poly dA-dT / metabolism
  • Rats
  • Substrate Specificity
  • Templates, Genetic

Substances

  • DNA, Circular
  • DNA, Single-Stranded
  • Poly dA-dT
  • DNA
  • DNA-Directed DNA Polymerase
  • Endonucleases