Asvrk. Rao et As. Balasubramanian, PHOSPHORYLATION OF CASEIN, FIBRINOGEN AND CALMODULIN BY A GLYCOPROTEIN PROTEIN-KINASE FROM MONKEY CEREBELLUM - A CASEIN KINASE II-LIKE ENZYME, Indian Journal of Biochemistry & Biophysics, 31(5), 1994, pp. 392-397
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.