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  • Title: Characterization of protein kinases from bovine parotid glands. The effect of tolbutamide and its derivative on these partially purified enzymes.
    Author: Kanamori T, Hayakawa T, Nagatsu T.
    Journal: Biochim Biophys Acta; 1976 Mar 11; 429(1):147-62. PubMed ID: 4116.
    Abstract:
    1. Four fractions of protein kinase (EC 2.7.1.37) activity (Peak IH, IIH, IIIC and IVC) have been resolved and partially purified from the 100 000 X g supernatant fraction of bovine parotid glands by DEAE-cellulose and phosphocellulose chromatographies. 2. The protein kinases of Peak IH and IIH were adenosine 3',5'-monophosphate (cyclic AMP) -dependent and had similar enzymic properties. The enzyme activities of Peak IIIC and IVC were cyclic-AMP independent, but there were some distinct differences between their properties. The protein kinase in Peak IIIC was activated by 0.2 M NaCl or KCl and phosphorylated casein preferentially as the substrate, utilizing only ATP as a phosphate donor. On the other hand, the protein kinase in Peak IVC was inhibited by univalent salts and preferred phosvitin to casein, utilizing either ATP or GTP as a phosphate donor. 3. Tolbutamide increased the Km value for ATP and the dissociation constant for cyclic AMP, resulting in the inhibition of cyclic-AMP dependent protein kinase activity in the presence of cyclic AMP. Tolbtamide and its carboxy derivative, 1-butyl-3-p-carboxyphenylsulfonylurea, exerted almost no inhibitory effect on either the cyclic-AMP dependent protein kinase activities in the absence of cyclic AMP or on the cyclic-AMP independent protein kinase activities.
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