Revisiting the binding kinetics and inhibitory potency of cardiac glycosides on Na+,K+-ATPase (α1β1): Methodological considerations

The data resolve discrepancies in the literature attributable to sub-optimal assay conditions. Similar IC50 values are obtained for pig kidney and recombinant human Na+,K+-ATPase, showing that inhibitory potencies are not determined by the species difference (pig versus human) or environment (membrane-bound versus detergent-soluble) of the Na+,K+-ATPase. The present methodological considerations are especially relevant for drug development of slow binding inhibitors.