The standard physiological direction of the Na+/K+ pump is to export 3 Na+, import 2 K+, and hydrolyze one ATP to ADP. Can it be driven backwards, importing 3 Na+, exporting 2 K+, and generating ATP? Does this happen in normal cells, and in what conditions?


All enzymes can theoretically catalyze the reverse reaction.

Researchers have driven the Na+/K+ ATPase to synthesize ATP with artificial ion concentrations:

We have studied the apparent affinity for K at its intracellular discharge sites by measuring the rate of ATP synthesis as a function of the internal K concentration in resealed red blood cell ghosts, where the Na-K pump is driven in reverse by the downhill efflux of K and influx of Na…

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  • $\begingroup$ But does it happen physiologically, or for cells in culture? $\endgroup$ – becko Nov 1 '17 at 18:45
  • $\begingroup$ @becko Oh sorry, I didn't see that part of your question. In the paper they drove the reaction with a very high ADP/ATP ratio which I expect wouldn't be found in cells. Technically it is possible for this reverse reaction to occur physiologically, but the ATPase activity will be dominant. $\endgroup$ – canadianer Nov 1 '17 at 19:15
  • $\begingroup$ So it seems that the answer is No. I'll wait a bit more before accepting your answer. Thanks again. $\endgroup$ – becko Nov 1 '17 at 20:57

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