title: Studies on a soluble human erythrocyte protein kinase.
abstract: A cyclic AMP-independent protein kinase has been isolated from human erythrocyte cytosol and purified about 28,000-fold. The enzyme uses ATP as the phosphoryl donor and exhibits a high activity towards casein and phosvitin. The kinase has a molecular weight of about 30,000 to 32,000 as estimated by sucrose density gradient centrifugation and Sephacryl S-200 gel filtration. Upon isoelectrofocusing, two kinase activities are resolved. The major component, which comprises about 85% of the activities, focuses at a pH of about 9.6 and the minor component at about 4.6. The relationship between these two kinase activities is not clear. NaF, ADP and, to a lesser extent, AMP, all inhibit the kinase activity. 2,3-Diphosphoglyceric acid, on the other hand, has no effect. The kinase also catalyzes the phosphorylation of a number of erythrocyte membrane proteins, including spectrin, band 3, and the sialoglycoproteins.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D004163:Diphosphoglyceric Acids / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007525:Isoelectric Focusing; D008970:Molecular Weight; D010774:Phosvitin / Q000378:metabolism; D011494:Protein Kinases / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology; D012995:Solubility; D013049:Spectrin / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D002364:Caseins; D004163:Diphosphoglyceric Acids; D013049:Spectrin; D000255:Adenosine Triphosphate; D012969:Sodium Fluoride; D010774:Phosvitin; D011494:Protein Kinases