title: Characterization of a cyclic nucleotide-independent protein kinase highly active in human adrenocortical carcinoma.
abstract: Study of the protein kinase activity pattern of four human adrenocortical carcinoma showed that in all the samples examined a histone kinase (HK III) activity was present at high level, whereas it was barely detectable in normal tissue. HK III was separated from other known adrenocortical protein kinases by diethylaminoethyl cellulose chromatography. Isolated HK III exhibited a histone (H2B) protamine-phosphotranferase selectivity and used adenosine triphosphate but not guanosine triphosphate as phosphate donor. Serine was identified as the only target amino acid phosphorylated in the protein substrate. HK III showed an apparent molecular weight of 65,000 upon gel filtration and an apparent sedimentation coefficient of 3.7S. HK III activity was cyclic adenosine 3':5'-monophosphate independent and was not influenced by calcium, calmodulin, polyamines, and heparin. The significance of HK III activity in adrenocortical carcinoma extracts at a high level as compared to that of normal tissue remains to be clarified with regard both to its possible relationship with tumoral cell growth and differentiation processes and to its potential interest as a marker of human tumoral tissue activity.
mesh_terms: D000306:Adrenal Cortex Neoplasms / Q000201:enzymology*; D002499:Centrifugation, Density Gradient; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D006656:Protamine Kinase / Q000032:analysis; D011494:Protein Kinases / Q000378:metabolism*; D013379:Substrate Specificity; D014018:Tissue Distribution
chemical_list: D000242:Cyclic AMP; D011494:Protein Kinases; D006656:Protamine Kinase