DNA topoisomerase I from calf thymus is inhibited in vitro by poly(ADP-ribosylation)

Eur J Biochem. 1983 Nov 2;136(2):391-6. doi: 10.1111/j.1432-1033.1983.tb07754.x.


A slight DNA topoisomerase I activity was detected in highly purified poly(ADP-Rib)polymerase prepared from calf thymus. This copurified activity was found to be suppressed under conditions where the poly(ADP-ribosylation) reaction occurs in the presence of NAD. Purified topoisomerase I from calf thymus was shown to be ADP-ribosylated by poly(ADP-Rib) polymerase purified from the same tissue. Poly(ADP-ribosylation) of topoisomerase I produces an inhibition of the enzymatic activity in parallel to the extent of ADP-ribosylation. The fact that a slight poly(ADP-Rib) polymerase activity was also found to copurify with a topoisomerase I preparation and that topoisomerase I activity can be modified by ADP-ribosylation, may suggest a spatial and functional correlation of these two enzymes in chromatin.

MeSH terms

  • Animals
  • Cattle
  • Chemical Phenomena
  • Chemistry
  • DNA Topoisomerases, Type I / isolation & purification*
  • In Vitro Techniques
  • Kinetics
  • NAD+ Nucleosidase / isolation & purification*
  • Poly Adenosine Diphosphate Ribose / pharmacology
  • Poly(ADP-ribose) Polymerases / isolation & purification*
  • Protein Binding
  • Thymus Gland / enzymology*
  • Topoisomerase I Inhibitors


  • Topoisomerase I Inhibitors
  • Poly Adenosine Diphosphate Ribose
  • Poly(ADP-ribose) Polymerases
  • NAD+ Nucleosidase
  • DNA Topoisomerases, Type I