[Separation of the enzyme catalyzing polymerization of deoxyribonucleoside diphosphates from preparations of E. coli DNA-polymerase I]

Mol Biol (Mosk). 1976 Nov-Dec;10(6):1231-7.
[Article in Russian]


The enzyme which catalyses template independent synthesis of polydeoxynucleotides from deoxynucleoside diphosphates was separated from E. coli DNA polymerase I by DEAE-cellulose chromatography followed by ultrafiltration through the M-50 Amicon filter. The ultrafiltration data indicate that the molecular weight of the enzyme is not higher than 50,000. The enzyme is not able to use deoxynucleoside triphosphates, ribonucleoside di- or triphosphates as substrates for the polymerization. The reaction of template independent polymerization proceeds with a lag period varying from 2 to 20 hours (for different preparations of enzyme) and is activated by Mg2+ (the optimal concentration 1-2 . 10(-3) M). The pH optimum of the reaction is at 8.5. The optimal concentration of deoxyribonucleoside diphosphates is 10(-3) M, and its increase strongly inhibits polymerization. The enzyme was supposed to be called deoxynucleoside diphosphate: olygonucleotide deoxynucleotidyltransferase (catalyzing polymerization without template). The presence of the enzyme in the preparations of E. coli DNA-polymerase I can explain the ability of the latter to catalyze the untemplated synthesis of poly dG : poly dC.

MeSH terms

  • DNA Polymerase I / metabolism*
  • DNA-Directed DNA Polymerase / metabolism*
  • Deoxyribonucleotides*
  • Enzyme Activation
  • Escherichia coli / enzymology*
  • Kinetics
  • Magnesium / pharmacology
  • Molecular Weight


  • Deoxyribonucleotides
  • DNA Polymerase I
  • DNA-Directed DNA Polymerase
  • Magnesium