Phosphorylation of fibrinogen by casein kinase 2.
Casein kinase 2 from rat liver cytosol phosphorylated human fibrinogen in a reaction that was not stimulated by Ca2+ or cyclic AMP, but was markedly inhibited by heparin, and proceeded at a similar rate when either ATP or GTP was used as phosphate donor. Analysis of casein kinase 2 by glycerol-density-gradient centrifugation showed that the activities towards fibrinogen, casein, phosvitin, high-mobility-group protein 14 and glycogen synthase coincided. Maximal incorporation into fibrinogen by casein kinase 2 averaged 1 mol of phosphate/mol of protein substrate, most of it in the alpha-chain, although some phosphorylation of the beta-chain was also detected. Analysis of phosphorylated alpha-chain revealed that most of the phosphate was incorporated on serine. Phosphorylation of human fibrinogen was also performed by casein kinase 2 from human polymorphonuclear leucocytes, lymphocytes and platelets.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D047388:Casein Kinases; D002499:Centrifugation, Density Gradient; D000242:Cyclic AMP / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005340:Fibrinogen / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D008099:Liver / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000097:blood / Q000378:metabolism*; D051381:Rats
D005340:Fibrinogen; D006493:Heparin; D000242:Cyclic AMP; D011494:Protein Kinases; D047388:Casein Kinases; D002118:Calcium