DNA polymerases and DNA topoisomerases solubilized from nuclear matrices of regenerating rat livers

Biochem Biophys Res Commun. 1984 Nov 14;124(3):917-24. doi: 10.1016/0006-291x(84)91045-3.


DNA topoisomerase activity together with the activities of DNA polymerase were detected in a form tightly associated with rat liver nuclear matrices. DNA polymerase activities were solubilized from the nuclear matrices of regenerating rat livers by sonic treatment followed by extraction of these activities with detergent and salt. The predominant activity was mainly alpha-polymerase as judged from the size determined by sucrose density gradient centrifugation. However, only beta-polymerase activity was detected in the matrix of normal rat livers. DNA topoisomerase activity, detected in both regenerating and normal liver nuclear matrices, showed a molecular size of about 4 S in sucrose gradient, and was active in the presence of EDTA. These results suggest that this enzyme belongs to type I topoisomerase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Nucleus / enzymology
  • Centrifugation, Density Gradient
  • DNA Topoisomerases, Type I / isolation & purification*
  • DNA-Directed DNA Polymerase / isolation & purification*
  • Liver / enzymology*
  • Liver Regeneration*
  • Rats
  • Rats, Inbred Strains


  • DNA-Directed DNA Polymerase
  • DNA Topoisomerases, Type I