Effect of nitroso compounds on Na/K-ATPase.
Thiol containing NO.-derivatives were found to inhibit the activity of brain and kidney Na/K-ATPase. S-Nitrosogluthatione 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. derivatives is discussed.
Boldyrev
A A
AA
Department of Biochemistry, School of Biology, International Biotechnological Center of M.V. Lomonosov Moscow State University, Russia. aab@atpase.bio.msu.su
Bulygina
E R
ER
Kramarenko
G G
GG
Vanin
A F
AF
D000818:Animals; D001921:Brain / Q000201:enzymology; D002417:Cattle; D004285:Dogs; D005609:Free Radicals; D005978:Glutathione / Q000737:chemistry; D007668:Kidney / Q000201:enzymology; D008565:Membrane Proteins / Q000378:metabolism; D009569:Nitric Oxide / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry
D005609:Free Radicals; D008565:Membrane Proteins; D009603:Nitroso Compounds; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D000254:Sodium-Potassium-Exchanging ATPase; D005978:Glutathione