The vacuolar H+-translocating ATPase of renal tubules contains a 115-kDa glycosylated subunit

Abstract

Kidney microsomes were fractionated with Triton X-114, to give a fraction enriched in the renal tubule H⁺-translocating ATPase, as judged by the sensitivity of its ATPase activity to bafilomycin A₁, and its content of two polypeptides recognized by antibodies directed against subunits of plant tonoplast ATPases. This fraction contained a polypeptide of apparent molecular mass of 115 kDa, that was recognized by an antibody to the largest (120 kDa) subunit chromaffin-granule membrane H⁺-ATPase, and, like this subunit, was reduced in molecular weight on treatment with glycopeptidase F. We conclude that, like other mammalian vacuolar H⁺-ATPases, the kidney H⁺-ATPase contains a large, glycosylated subunit.