Characterization of an arginine‐specific protein kinase tightly bound to rat liver DNA

Abstract

A new protein kinase has been characterized among the proteins tightly bound to rat liver DNA and released by DNase I and RNase A treatment. This enzyme was separated by gel filtration from this released material. Its apparent molecular mass was found to be 34 kDa and it is made of a single unit. The main characteristic of this protein kinase is that it is arginine‐specific. Isolation of phosphoarginine required the use of proteolytic enzymes at alkaline pH since the phosphate bond is highly acid‐labile. This protein kinase is able to autophosphorylate and to phosphorylate a single chromosomal protein of 11 kDa also tightly bound to DNA. It uses ATP and dATP as phosphate donors and is cAMP‐independent. Its optimal activity requires Mn2+ ions. Vanadate, spermine and heparins have no effect on its activity. Copyright © 1987, Wiley Blackwell. All rights reserved