Identification of an 82,000-dalton protein responsible for K+/H+ antiport in rat liver mitochondria.
Under highly selective conditions, pretreatment of rat liver mitochondria with N,N'-dicyclohexylcarbodiimide (DCCD) results in 95% inhibition of K+/H+ antiport. This inhibition is irreversible. The K+/H+ antiporter is reversibly inhibited by physiological (Mg2+ and H+) and pharmacological (quinine and propranolol) inhibitors. Each of these inhibitors protects the K+/H+ antiporter against inhibition by DCCD. DCCD is without effect on Na+/H+ antiport under all conditions tested, confirming our contention that rat liver mitochondria possess two different alkali cation/proton antiporters (Nakashima, R. A., and Garlid, K. D. (1982) J. Biol. Chem. 257, 9252-9254). The selective nature of irreversible inhibition by DCCD has enabled us to label and identify the protein responsible for K+/H+ antiport. This protein, the first cation antiporter so identified, migrates on sodium dodecyl sulfate-polyacrylamide gels with a molecular weight of 82,000.
D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D007700:Kinetics; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D008970:Molecular Weight; D011188:Potassium / Q000378:metabolism*; D027961:Potassium-Hydrogen Antiporters; D011433:Propranolol / Q000494:pharmacology; D011803:Quinine / Q000494:pharmacology; D051381:Rats
D002352:Carrier Proteins; D027961:Potassium-Hydrogen Antiporters; D004024:Dicyclohexylcarbodiimide; D011433:Propranolol; D011803:Quinine; D011188:Potassium