Potassium-transporting ATPase alpha chain 2 (Atp12a) is a non-gastric H,K-ATPase that functions as an H+,NH4(+)-ATPase []. It belongs to the small IIC subfamily of P-type ATPases, whose members function with a beta-subunit to transport K+ into the cell in exchange for either Na+ or H+ []. Instead of having its own beta-subunit, Atp12a uses the beta1-subunit of Na,K-ATPase []. In humans, it is localised in distal kidney and may be involved in H(+)/Na(+) and/or H(+)/NH(4)(+) transport [].
