Diamide blocks H+ conductance in mitochondrial H+-ATPase by oxidizing FB dithiol.
Effects of diamide on proton conductance of electron transport particles (ETPH), purified H+-ATPase (F1-F0), F0 of the H+-ATPase from beef heart mitochondria and binding of cadmium (109Cd) to the H+-ATPase have been examined in the present paper. When ETPH and purified H+-ATPase are treated with 1 mM diamide, ATP-dependent generation of membrane potential, monitored by the absorbance change produced by the redistribution of oxonol VI, is consistently inhibited. Diamide also blocks passive H+ conductance driven by a K+ diffusion potential in the membrane sector, F0, of H+-ATPase. Furthermore, diamide treatment drastically reduces the binding of 109Cd2+ to H+-ATPase, showing competition for the FB dithiol group.
Huang
Y
Y
Pringle
M J
MJ
Sanadi
D R
DR
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D002104:Cadmium / Q000378:metabolism; D002417:Cattle; D003958:Diamide / Q000494:pharmacology*; D004579:Electron Transport / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D008929:Mitochondria, Heart / Q000201:enzymology*; D025261:Mitochondrial Proton-Translocating ATPases; D010084:Oxidation-Reduction; D010086:Oxidative Phosphorylation Coupling Factors; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011522:Protons; D011868:Radioisotopes; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D001391:Azo Compounds; D010086:Oxidative Phosphorylation Coupling Factors; D011522:Protons; D011868:Radioisotopes; D013438:Sulfhydryl Compounds; D002104:Cadmium; D003958:Diamide; D000251:Adenosine Triphosphatases; C032410:coupling factor B; D025261:Mitochondrial Proton-Translocating ATPases; D006180:Proton-Translocating ATPases