[Study of ADP effect on brain Na+, K+-ATPase].
A mechanism of K-insensitive, ouabain-dependent liberation of Na+ from the cell during an increase in ADP intracellular concentration is studied. It is shown that the increase in the ADP/ATP ratio does not change the Na+, K+-ATPase affinity to K+ ions and does not result in the Na-activated, K-independent ATPase reaction. ADP protects ATPase from the inhibition by ouabain which is accounted for by a decrease in the concentration of a glycoside-sensitive form of the enzyme E2-P due to a turnover of the phosphokinase step of the reaction, but not due to the binding of free Mg2+ ions. The results obtained suggest that the increase in ADP concentration within the cell activates Na-Nan exchange along Na-transporting channels of the ionic pump.
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D004789:Enzyme Activation; D011188:Potassium; D012964:Sodium / Q000378:metabolism
D000244:Adenosine Diphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium
Izuchenie vliianiia ADP na Na+, K+- ATPazu mozga