Mitochondrial inner membrane anion channel. Regulation by divalent cations and protons

Journal Article · Thu Nov 05 04:00:00 EST 1987 · J. Biol. Chem.; (United States)

OSTI ID:5664149

Beavis, A D; Garlid, K D

It is now well established that incubation of mitochondria at pH 8 or higher opens up an electrophoretic anion transport pathway in the inner membrane. It is not known, however, whether this transport process has any physiological relevance. In this communication we demonstrate that anion uniport can take place at physiological pH if the mitochondria are depleted of matrix divalent cations with A23187 and EDTA. Using the light-scattering technique we have quantitated the rates of uniport of a wide variety of anions. Inorganic anions such as Cl-, SO4(2-), and Fe(CN)6(4-) as well as physiologically important anions such as HCO/sub 3/-, Pi-, citrate, and malate are transported. Some anions, however, such as gluconate and glucuronate do not appear to be transported. On the basis of the finding that the rate of anion uniport assayed in ammonium salts exhibits a dramatic decline associated with loss of matrix K+ via K+/H+ antiport, we suggest that anion uniport is inhibited by matrix protons. Direct inhibition of anion uniport by protons in divalent cation-depleted mitochondria is demonstrated, and the apparent pK of the binding site is shown to be about 7.8. From these properties we tentatively conclude that anion uniport induced by divalent cation depletion and that induced by elevated pH are catalyzed by the same transport pathway, which is regulated by both matrix H+ and Mg2+.

• Research Organization: Medical College of Ohio, Toledo
• OSTI ID: 5664149
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 262:31; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID CARBONATES
AMINO ACIDS
ANIMALS
ANIONS
BARYONS
BIOLOGICAL PATHWAYS
CARBOXYLIC ACIDS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CHELATING AGENTS
CHLORIDES
CHLORINE COMPOUNDS
EDTA
ELECTROPHORESIS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
HALIDES
HALOGEN COMPOUNDS
INHIBITION
IONS
IRON
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
METALS
MITOCHONDRIA
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
OXYGEN COMPOUNDS
PH VALUE
PHOSPHATES
PHOSPHORUS COMPOUNDS
PROTONS
RATS
RODENTS
SULFATES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
VERTEBRATES