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 this glycoprotein is not known. Some specific sequence of the beta subunit can modulate the activation of the Na,K-pump by extracellular potassium ions. The sodium/potassium-transporting ATPase is composed of a catalytic alpha subunit, an auxiliary non-catalytic beta subunit and an additional regulatory subunit. Abundantly in brain, eye and testis, at a lower extent in spleen. Belongs to the X(+)/potassium ATPases subunit beta family.