A novel endonuclease of 55-kDa was found in rat liver mitochondria by a zymographic assay, in addition to the 29 kDa enzyme that is well-known as endonuclease G (Endo G). Subcellular localization of these enzymes in rat liver cells was examined by biochemical fractionation. Endo G was located in both nuclei and mitochondria as has been previously reported, while the 55-kDa enzyme was only detec...
