Effect of starvation, diabetes and insulin on the casein kinase 2 from rat liver cytosol

Abstract

Starvation, diabetes and insulin did not alter the concentration of casein kinases in rat liver cytosol. However, the Km for casein of casein kinase 2 from diabetic rats was about 2-fold lower than that from control animals. Administration of insulin to control rats did not alter this parameter, but increased the Km for casein of casein kinase 2 in diabetic rats. Starvation did not affect the kinetic constants of casein kinases. The effect of diabetes on casein kinase 2 persisted after partial purification of the enzyme by glycerol-density-gradient centrifugation and affected also its activity on other protein substrates such as phosvitin, high-mobility-group protein 14 and glycogen synthase. The results indicate that rat liver cytosol casein kinase 2 is under physiological control.

Phosphorylation of fibrinogen by casein kinase 2

“…The source of all the reagents used in this work, including human fibrinogen and other protein substrates, was as previously reported (Itarte et al, 1983;Martos et al, 1985).…”

“…Rat liver casein kinases 1 and 2 were purified as previously described (Martos et al, 1985). The purified preparation of casein kinase 2 had a specific activity of about 90 units/mg of protein and contained only the Mr-41 000 and Mr-27 000 polypeptides present in casein kinases 2 purified from other sources (Hathaway & Traugh, 1982).…”

Protein kinase CK2 is altered in insulin‐resistant genetically obese (fa/fa) rats

“…The effect of insulin on protein kinase CK2 in whole animals and in cell cultures is a matter of controversy concerning not only the response induced but also its link to changes in CK2 protein content [9, 18–20]. Previous studies in streptozotocin‐diabetic rats [21, 22]have shown that total protein kinase CK2 activity per g of tissue was unaffected in liver and skeletal muscle, although in the latter the specific activity of the enzyme decreased by 30%. On the other hand, protein kinase CK2 activity in human skeletal muscle from insulin‐resistant non‐diabetic patients was found to be higher than that from normal insulin‐sensitive or insulin‐resistant diabetic humans but no differences in CK2 protein were detected either between the three groups [23].…”

Phosphorylation of Rat Liver Mitochondrial Glycerol-3-phosphate Acyltransferase by Casein Kinase 2

“…The elevated enzyme activity in the presence of ATP or GTP is probably because of phosphorylation. CK2 is present in rat liver cytosol and appears to be under physiological control (44). An 85-kDa 32 Plabeled band corresponding to mtGAT was detected when isolated MOM was incubated with [␥-…”