High molecular weight deoxyribonucleic acid polymerase from crown gall tumor cells of periwinkle (Vinca rosea)

Biochemistry. 1976 Feb 10;15(3):688-97. doi: 10.1021/bi00648a037.


A high molecular weight (6 S) plant DNA polymerase from axenic Vinca rosea tissue culture cells has been purified 2200-fold and characterized. The enzyme has a molecular weight of 105 000 (+/-5000). Sodium dodecyl sulfate-acrylamide gel electrophoresis of the purified enzyme yields polypeptide subunits having molecular weights of 70 000 and 34 000. The purified enzyme has a pH optimum of 7.5; a cation requirement optimum of 6 mM Mg2+ or 0.5 mM Mn2+; an apparent requirement for Zn2+; a Km of 1 muM for dTTP; and a 3.5-fold stimulation by 50 mM KCl. The enzyme is sensitive to N-ethylmaleimide (1 mM), heparin (0.1 muM), ethanol (5%), pyrophosphate (0.05 muM), and o-phenanthroline (0.1 mM) but is insensitive to rifamycin. Denatured DNA is found to be the best natural template, and only negligible activity can be demonstrated with the ribopolymer templates poly(dT)n-poly(rA)n and p(dT)10-poly(rA)n. In addition to the polymerization reaction, the enzyme catalyzes a pyrophosphate exchange reaction. Antibody to calf thymus 6-8S DNA polymerase does not inhibit DNA polymerase from Vinca rosea, suggesting no antigenic relationships between the mammalian and plant enzymes.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding, Competitive
  • Cations, Monovalent
  • DNA Nucleotidyltransferases / isolation & purification
  • DNA Nucleotidyltransferases / metabolism*
  • Enzyme Activation / drug effects
  • Hydrogen-Ion Concentration
  • Magnesium / pharmacology
  • Manganese / pharmacology
  • Molecular Weight
  • Plant Tumors*
  • Plants / enzymology*
  • Templates, Genetic
  • Zinc / pharmacology


  • Cations, Monovalent
  • Manganese
  • DNA Nucleotidyltransferases
  • Magnesium
  • Zinc