[Regulation of Na, K-ATPase activity by monovalent cations].
A deviation from optimal conditions of the Na, K-ATPase reaction results in a drastic change in the plot: enzyme activity versus Na/K ratio. Acidification of the medium and a decrease in Mg2+ concentration and temperature results in two peaks on the curve at Na/K ratio of about 1 and at Na/K ratio greater than 4. The enhancement of pH of the medium and increase in Mg2+ concentration decreases the first peak and increases the second one. A comparison of these curves for hydrolysis of ATP, UTP and p-nitrophenylphosphate and temperature dependence of the hydrolysis of the substrates suggest that the anomalies observed may be accounted for the Na+ effect on the K-sites or K+ effect on the Na-sites under conditions when cation-binding sites are heterogeneous.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001665:Binding Sites; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D009994:Osmolar Concentration; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology*; D013696:Temperature
D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium
Reguliatsiia aktivnosti Na, K-ATPazy odnovalentnymi kationami.