Kinetic cooperativity change after H2O2 modification of (Na,K)-ATPase

• Published in: The Journal of biological chemistry Vol. 259; no. 12; pp. 7712 - 7718
• Main Authors: Garner, M H, Garner, W H, Spector, A
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 25.06.1984; American Society for Biochemistry and Molecular Biology
• Subjects: Adenosine Triphosphate - metabolism; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cattle; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide - metabolism; Hydrolases; Hydrolysis; Kidney Medulla - enzymology; Kinetics; Lens, Crystalline - enzymology; Mathematics; Nitrophenols - metabolism; Organophosphorus Compounds - metabolism; Sodium-Potassium-Exchanging ATPase - metabolism; Enzyme; Molecular interaction; Hydrogen Peroxides; Biological activity; Kidney; Vertebrata; Chemical modification; Mammalia; Sodium; Na,K-ATPase; Lens; Artiodactyla; Beef; Kinetics; Catalyst activity; Potassium; Ungulata
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)42851-1

The kinetics of hydrolysis of ATP and p-nitrophenylphosphate and the action of the allosteric effectors, Na+ and K+, upon the hydrolysis of these substrates were used to study the H2O2-modified, uncoupled (Na,K)-ATPase isolated from cultured bovine lenses ( Garner , W. H., Garner , M. H., and Spector , A. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 2044-2048). Pure bovine renal (Na,K)-ATPase was modified by H2O2 in 150 mM KCl and 20 mM MgCl2 to yield an enzyme with kinetic properties similar to the enzyme isolated from the H2O2-treated, cultured bovine lens. H2O2 modification changes the interaction of the ATP hydrolysis site from negative to positive kinetic cooperativity. H2O2 modification dramatically alters Na+ stimulation of ATP hydrolysis and Na+ inhibition of p-nitrophenylphosphate hydrolysis while having little effect upon K+ control of the hydrolysis of these two substrates.