Sodium pump that utilizes the energy of pyrophosphate hydrolysis as the driving force for Na(+) movement across the membrane. diphosphate + H2O + Na(+)(in) = H(+) + Na(+)(out) + 2 phosphate Inhibited by GdCl3. Requires K(+) for maximal activity. K(+) greatly stimulates Na(+) binding. Thermostability depends on the binding of Mg(2+). Optimum temperature is 70 degrees Celsius. Homodimer. Has 16 transmembrane helices and a cytoplasmic domain that contains the active site. Pyrophosphate binding is thought to trigger a conformation change that allows Na(+) release. Has at least two binding sites for Na(+) (PubMed:22837527). Belongs to the H(+)-translocating pyrophosphatase (TC 3.A.10) family. K(+)-stimulated subfamily.