Abstract
Polynucleotide ligase, which catalyzes covalent joining of two segments of an interrupted strand in a DNA duplex, was studied with normal rat liver, regenerating rat liver and hepatoma induced by N-2-fluorenylacetamide. The activity is located in both nuclei and soluble fractions. Its optimal pH was 8.0. The enzyme requires ATP as a cofactor. Its activity was completely dependent on the presence of Mg2+. The activities of these enzymes in regenerating rat liver were 4 times higher, in both fractions, than those in normal rat livers, whereas in hepatoma they were about 5 times higher in soluble fraction, and about 3 times higher in nuclear fraction than those in normal rat liver.
