The proton translocating ATPase responsible for urinary acidification

Abstract

H+ secretion by the turtle urinary bladder is produced by a proton pump located in the luminal membrane. We show that a microsomal fraction of these cells contains an electrogenic proton translocating ATPase that is inhibited by dicyclohexylcarbodiimide but not oligomycin or vanadate. On a sucrose density gradient, this ATPase co-migrated with luminal membranes labeled with concanavalin A, but was separate from a lysosomal marker. This enzyme is therefore the H+ ATPase that causes urinary acidification.