Characterization of two casein kinase activities in the fungus Mucor rouxii
Two cyclic-nucleotide independent soluble casein kinase activities (CK I and CK II) from the fungus Mucor rouxii have been isolated, characterized and found to fit in the general classification of type 1 (CK I) and 2 (CK II) casein kinases, according to their enzymatic and structural properties. Bot...
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| Autores principales: | , |
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1988
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08957479_v12_n4_p183_Pardo http://hdl.handle.net/20.500.12110/paper_08957479_v12_n4_p183_Pardo |
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| Sumario: | Two cyclic-nucleotide independent soluble casein kinase activities (CK I and CK II) from the fungus Mucor rouxii have been isolated, characterized and found to fit in the general classification of type 1 (CK I) and 2 (CK II) casein kinases, according to their enzymatic and structural properties. Both enzymes phosphorylate acidic substrates, require Mg2+ and have a chromatographic behaviour on DEAE-Sepharose and phosphocellulose similar to their mammalian counterparts. CK I has a sedimentation coefficient of 3.5 S, uses ATP as a phosphate donor (K(m) = 40 μM), phosphorylates casein mainly on serine residues, its activity is strongly inhibited by KCl and polyamines. CK II has a sedimentation coefficient of 7.4 S, uses ATP and GTP as phosphate donors (K(m) ATP = 10 μM; K(m) GTP = 40 μM), phosphorylates casein in serine and threonine, its activity is stimulated by KCl and by polyamines and is inhibited by heparin (I50 = 0.5 μg/ml). Casein kinase activity associated to particulate fraction (40% of total) has been partially characterized and shown to be similar to the soluble CK I activity. |
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