Soluble cAMP-independent protein kinase from human spleen.
A protein kinase (EC 2.7.1.37) was purified 2000-fold, from the soluble protein fraction of human spleen cells, using ion-exchange chromatography, ammonium sulfate fractionation, and gel filtration. This rapid procedure yielded 30% of the initial activity and an enzyme preparation with specific activity of 62 nmol min-1 mg-1 of protein. On the basis of disc gel electrophoresis in sodium dodecyl sulfate acrylamide gels and isoelectric focusing the enzyme preparation appears homogeneous and to consist of one polypeptide with a molecular weight of 43,000 and having a pI of 7.1. The purified enzyme activity is cyclic AMP and cGMP independent phosphorylates both alpha-casein and phosvitin, and uses Mg2+ ATP and Mg2+ GTP as phosphate donors, exhibiting an apparent Km of 2.0 and 6.6 X 10(-5)m, respectively. Furthermore, the enzyme activity is strongly inhibited by heparin (K50 = 0.1 micrograms/ml). These catalytic properties are characteristic of the enzyme casein kinase II, as described in several eukaryotic cells.
Gounaris
A
A
Department of Biochemistry, Papanikolaou Research Center, Hellenic Anticancer Institute, Greece.
Trangas
T T
TT
Tsiapalis
C M
CM
D000255:Adenosine Triphosphate / Q000378:metabolism; D002850:Chromatography, Gel; D000242:Cyclic AMP / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D011494:Protein Kinases / Q000378:metabolism*; D013154:Spleen / Q000201:enzymology*; D013379:Substrate Specificity
C036852:magnesium GTP; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D011494:Protein Kinases