IN-VITRO PHOSPHORYLATION OF PROTEINS TIGHTLY BOUND TO DNA BY PROTEIN KINASE-NII

1. Highly purified DNA from calf thymus was phosphorylated with protei n kinase NII. 2. Digestion with proteinase K of this DNA demonstrates proteins as phosphorylated component. 3. Gel filtration chromatography on Bio-Gel A-0.5m gel column shows a major protein peak between 50 an d 70 kDa. 4. SDS gel electrophoresis, after hydrolysis, to digest comp letely DNA, shows three major phosphorylated bands corresponding to po lypeptides of Mr between 31 and 21 kDa. 5. After high voltage electrop horesis on TLC plates tryptic digested polypeptides show very similar phosphopeptides patterns.