Abstract
SODIUM and potassium ions are both required to activate the (Na+ + K+)-dependent–ATPase and each inhibits activation by the other1. The K+ activates the turnover of enzyme hyperbolically at low Na+ concentrations, but with increasing concentrations of Na+ the activation curve becomes sigmoid2. Similarly at low concentrations of K+, the Na+ activation curve is hyperbolic but at high concentrations of K+ it becomes sigmoid1. These data indicate the presence of at least two Na+ and/or K+ sites, respectively, but do not indicate the mechanism of interaction between these ions or sites3. Priestland and Whittam2, and others, have suggested that direct competition between the cations for the activating sites can account for the sigmoidal activation curves in the presence of high concentrations of the other cation. Alternatively, Robinson4 has argued that the sigmoidal activation curves, which are consistent with the heterotropic effects of an allosteric activator5, are evidence for allosteric interactions in the (Na+ + K+)–ATPase. In support of this hypothesis he has presented evidence for a co-operativity in the K+ activation of the p-nitrophenyl-phosphatase activity of the (Na+ + K+)–ATPase4. As Garrahan6 has pointed out, however, these data are not conclusive.
Similar content being viewed by others
References
Skou, J. C., Biochim. Biophys. Acta, 23, 394 (1957).
Priestland, R. M., and Whittam, R., Biochem. J., 109, 369 (1968).
Sachs, J. R., and Welt, L. G., J. Clin. Invest., 46, 1433 (1967).
Robinson, J. D., Nature, 220, 1325 (1968).
Monod, J., Wyman, J., and Changeux, J. P., J. Mol. Biol., 12, 88 (1965).
Garrahan, P. J., Nature, 222, 1000 (1969).
Tobin, T., and Sen, A. K., Abstr. Fourth Intern. Cong. Pharmacol., 199 (1969).
Tobin, T., and Sen, A. K., Biochim. Biophys. Acta (in the press).
Tobin, T., Banerjee, S. P., and Sen, A. K., Irish J. Med. Sci. (in the press).
Banerjee, S. P., and Sen, A. K., Fed. Proc., 28, 1846 (1969).
Gerhart, J. C., and Pardee, A. B., J. Biol. Chem., 237, 891 (1962).
Monod, J., Changeux, J. P., and Jacob, F. J., Mol. Biol., 6, 306 (1963).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
TOBIN, T., BANERJEE, S. & SEN, A. Allosteric Interactions in (Na+ + K+)-ATPase. Nature 225, 745–746 (1970). https://doi.org/10.1038/225745a0
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1038/225745a0
- Springer Nature Limited
This article is cited by
-
Effect of cardiac glycosides and sodium ethacrynate on transepithelial sodium transport inin vivo micropuncture experiments and on isolated plasma membrane Na?K ATPasein vitro of the rat
Pfl�gers Archiv European Journal of Physiology (1972)
-
Cooperative Interactions in Energy-dependent Accumulation of Ca2+ by Isolated Rat Liver Mitochondria
Nature New Biology (1971)