title: Purification and characterization of two cyclic AMP-independent protein kinases from AH-66 hepatoma ascites cells.
abstract: Casein kinase 1 (CK 1) and casein kinase 2 (CK 2) were purified from the cytosol fraction of AH-66 cells to electrophoretic homogeneity by a simple procedure based on our finding that CK 1 and CK 2 are chromatographically distinct on phosvitin-Sepharose. The amino acid composition of CK 2 resembles those of cyclic AMP-dependent and cyclic GMP-dependent protein kinases but is considerably different from that of CK 1. Both CK 1 and CK 2 were markedly stimulated by low concentrations of spermine and spermidine but were practically unaffected by putrescine. When CK 1 and CK 2 were added back to AH-66 cytosol, they promoted the phosphorylation of the same cytosolic proteins that were phosphorylated endogenously. Although most of the cytosolic proteins phosphorylated by CK 1 and CK 2 were common, some proteins were preferentially phosphorylated by either CK 1 or CK 2. Interestingly, CK 1 was able to phosphorylate the plasma membrane proteins of AH-66 cells. In contrast, enhancement of the phosphorylation of the membrane proteins by CK 2 was practically undetectable.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002621:Chemistry; D003600:Cytosol / Q000201:enzymology; D004586:Electrophoresis / Q000379:methods; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008970:Molecular Weight; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification* / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D011494:Protein Kinases