Comparison of biochemical properties of DNA-topoisomerase I from normal and regenerating liver - Sorbonne Université
Journal Articles European Journal of Biochemistry Year : 1992

Comparison of biochemical properties of DNA-topoisomerase I from normal and regenerating liver

Abstract

Biochemical properties of topoisomerase I from normal and regenerating rat liver were analysed using crude or fractionated nuclear extracts. We could not detect significative change in topoisomerase I content or activity (magnesium stimulation and inhibition by ATP) during the course of liver regeneration. Topoisomerase I can be resolved into two species of 97 kDa and 100 kDa, with the same pI of 8.2-8.6 as shown by two dimensional gel electrophoresis. The two polypeptides contained a non-phosphorylated precursor and others forms with variable degrees of phosphorylation. In-vitro dephosphorylation with alkaline phosphatase leads to the disappearance of the phosphorylated forms and inactivation of the enzyme. The affinity of topoisomerase I for chromatin (measured by salt elution) differs markedly between normal and regenerating liver: nearly 50% of topoisomerase I remained bound to the chromatin from normal liver at 250 mM NaCl whereas it was completely eluted from 24-h-regenerating-liver nuclei. The biological significance of these results is discussed.

Dates and versions

hal-04041393 , version 1 (22-06-2023)

Identifiers

Cite

Marie-Francoise Tournier, Joelle Sobczak, Beatrice De Nechaud, Michel Duguet. Comparison of biochemical properties of DNA-topoisomerase I from normal and regenerating liver. European Journal of Biochemistry, 1992, 210 (1), pp.359-364. ⟨10.1111/j.1432-1033.1992.tb17429.x⟩. ⟨hal-04041393⟩
10 View
6 Download

Altmetric

Share

More