Diphosphopyridine nucleotide pyrophosphorylase in the nuclei isolated from poisoned and regenerating rat liver

Abstract

The procedure of Hogeboom et al. (1952) for the isolation of liver nuclei has been modified. Some properties of the iso-lated nuclei have been examined. They do not catalyse a [p32]phosphate-adenosine triphosphate exchange reaction but they do contain more adeno-sine triphosphatase activity than can be explained by contamination with mitochondria. Little change was found in the specific activity of diphos-phopyridine nucleotide pyrophosphorylase of nuclei isolated from livers of rats poisoned with the hepatotoxic agents beryllium, CCl4, dimethyl-nitrosamine and ethionine. After partial hepatectomy, the specific activity of diphosphopyridine nucleotide pyrophosphorylase of nuclei isolated from the regenerating liver falls continuously for 3 days to approximately half of its control value.