On the stoichiometry between uncouplers of oxidative phosphorylation and respiratory chains. The catalytic action of SF 6847 (3,5-di-tert-butyl-4-hydroxy-benzylidenemalononitrile).
Titration of State 4 rat-liver mitochondria at pH 7.2 with the uncoupler 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847) at various concentrations of mitochondria and using various substrates indicates that under optimal conditions less than 0.2 molecule of 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile per respiratory chain is sufficient to induce complete uncoupling. This result suggests that there is not a stoichiometric relationship between uncoupler molecules and cytochrome c oxidase, involved in oxidative phosphorylation, or between the former and phosphorylation assemblies. Experiments on the release by 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile of azide-inhibited respiration of State 3 mitochondria and titrations with 5-chloro-3-tert-butyl-2'-chloro-4'-nitrosalicylanilide (S13) of State 4 mitochondria at various mitochondrial concentrations confirm this conclusion.
D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D001386:Azides / Q000494:pharmacology; D001597:Benzylidene Compounds / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008314:Malonates / Q000494:pharmacology; D008930:Mitochondria, Liver; D009570:Nitriles / Q000494:pharmacology*; D009574:Nitro Compounds / Q000494:pharmacology; D010085:Oxidative Phosphorylation; D051381:Rats; D012457:Salicylamides / Q000494:pharmacology; D013386:Succinates / Q000378:metabolism; D013772:Tetramethylphenylenediamine / Q000378:metabolism; D014475:Uncoupling Agents / Q000494:pharmacology*
D000814:Aniline Compounds; D001386:Azides; D001597:Benzylidene Compounds; D003580:Cytochromes; D008314:Malonates; D009570:Nitriles; D009574:Nitro Compounds; D012457:Salicylamides; D013386:Succinates; D014475:Uncoupling Agents; C001784:SF 6847; D013772:Tetramethylphenylenediamine; D001205:Ascorbic Acid