Effect of nitroso compounds on Na/K-ATPase
1997
Boldyrev, A.A. | Bulygina, E.R. | Kramarenko, G.G. | Vanin, A.F.
Thiol containing NO radical-derivatives were found to inhibit the activity of brain and kidney Na/K-ATPase. S-Nitrosoglutathione demonstrated only minor inhibiting activity while dinitrosyl iron complexes (DNIC) with cysteine or glutathione were much more effective. Brain Na/K-ATPase is more vulnerable to inhibiting action than kidney Na/K-ATPase. Inhibition of the activity is accompanied by a decrease in amount of protein thiol groups and a change in the substrate dependence curve of the enzyme. Restoration of Na/K-ATPase activity by SH-reagent dithiothreitol or cysteine is accompanied by restoration of SH-groups of the enzyme. This suggests that blockade of SH-groups of Na/K-ATPase is responsible for the inhibition. The possibility that this blockade results in disordering of interprotomer interactions within the oligomeric complexes of Na/K-ATPase is suggested. Possible regulatory meaning of the effect of NO radical derivatives is discussed.
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