ATP1B3 belongs to the X(+)/potassium ATPases subunit beta family. This is the non-catalytic component of the active enzyme, which catalyzes the hydrolysis of ATP coupled with the exchange of Na+ and K+ ions across the plasma membrane. The exact function of the beta-3 subunit is not known. Recombinant human ATP1B3 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.