Nuclear protein kinases from murine cells

Abstract

Three protein kinase activities are found in nuclei from three different murine cells (Ehrlich ascites cells, mouse L cells and rat glioma cells). Two of these activities are soluble, one is bound to chromatin. The soluble enzymes are similar, if not identical, to the cytoplasmic protein kinases. The chromatin-bound, adenosine-cyclic-3':5'-monophosphate-independent enzyme is not found in the cytoplasm. This enzyme is composed of one subunit with a molecular weight of 80000-90000. Some biochemical properties of this enzyme are described. A brief description of a nuclear enzyme, which dephosphorylates phosphorylated histones, is also given.