Properties and regulation of the renal vacuolar H(+)-ATPase and H(+)-K(+)-ATPase.

Two proton-transporting ATPases participate in active proton transport in the nephron: the electrogenic vacuolar H(+)-ATPase and the electroneutral H(+)-K(+)-ATPase. The vacuolar H(+)-ATPase participates in proximal and distal hydrogen ion secretion related to acid-base homeostasis. The H(+)-K(+)-ATPase is located exclusively in the distal nephron, and its primary role may be in active potassium reabsorption. The properties, distribution, and regulation of these two enzymes are discussed.