PHOSPHORYLATION OF CASEIN, FIBRINOGEN AND CALMODULIN BY A GLYCOPROTEIN PROTEIN-KINASE FROM MONKEY CEREBELLUM - A CASEIN KINASE II-LIKE ENZYME

A glycoprotein protein kinase was isolated from monkey cerebellum by p olylysine-Sepharose chromatography acid affinity chromatography on Sep harose 4B coupled to the lectin, Concanavalin A, The protein kinase ph osphorylated casein on serine and threonine residues and was stimulate d by polylysine, polyarginine, spermine, histone, protamine and sphing osine, but was inhibited by heparin, poly (Glu, Ala, Tyr) and poly (Gl u, Tyr). These characteristics were typical of casein kinase II. The p rotein kinase also phosphorylated fibrinogen and calmodulin and exhibi ted similar characteristics of stimulation by polylysine or polyargini ne. The phosphorylation of fibrinogen (a glycoprotein), but not casein or calmodulin (non-glycoproteins), was significantly inhibited by Con canavalin A. Unlike casein kinase II, the enzyme did not undergo autop hosphorylation. The collective results suggested that the enzyme from monkey cerebellum was a casein kinase II-like protein kinase and that phosphorylation of a glycoprotein substrate (fibrinogen) by the kinase could be influenced by a carbohydrate binding lectin.