Study on regulatory properties of a soluble nucleoside triphosphatase from bovine kidney
Soluble NTPhase preparation with specific activity of 80 U per mg of protein was obtained from bovine kidney. The purification scheme included the enzyme extraction followed by salting out and column chromatography on Molselect G-75, DEAE-Toyopearl 650M, Toyopearl HW 60, Sephadex G-200, Hydroxyapatite and Sephacryl S-200. NTPhase activity has been found to be affected with physiological concentrations of fructose 1,6-diphosphate, ATP and PPi, the first one being an activator in the whole range of concentrations tested (0.01-5 mM). At low concentrations, 1-2 mM and 0.2-0.6 mM accordingly, ATP and PPi activated the enzyme, while at higher concentrations inhibitory effects were observed. Our results suppose that fructose 1,6-diphosphate, ATP and PPi regulate NTPhase activity in vivo.