Mediates electrogenic transport of potassium as well as sodium. Acts probably as a potassium-sodium cotransporter. Major sodium reentry pathway at high pH values. Mutants are defective in potassium accumulation at high pH and lack KtrII activity. Disruption does not affect Na(+)-ATPase activity. Belongs to the TrkH potassium transport family. Was originally thought to be part of the V-type sodium ATP synthase. Truncated N-terminus.