title: Template specificity of rat mitochondrial DNA polymerase.
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: D000818:Animals; D004247:DNA / Q000378:metabolism; D004270:DNA, Circular / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism; D066298:In Vitro Techniques; D008930:Mitochondria, Liver / Q000201:enzymology*; D011067:Poly dA-dT / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity; D013698:Templates, Genetic
chemical_list: D004270:DNA, Circular; D004277:DNA, Single-Stranded; D011067:Poly dA-dT; D004247:DNA; D004259:DNA-Directed DNA Polymerase; D004720:Endonucleases