Enhancement of hydrogen peroxide formation by protophores and ionophores in antimycin-supplemented mitochondria

Biochem J. 1980 Apr 15;188(1):31-7. doi: 10.1042/bj1880031.


Rat and pigeon heart mitochondria supplemented with antimycin produce 0.3-1.0nmol of H(2)O(2)/min per mg of protein. These rates are stimulated up to 13-fold by addition of protophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone, carbonyl cyanide m-chloromethoxyphenylhydrazone and pentachlorophenol). Ionophores, such as valinomycin and gramicidin, and Ca(2+) also markedly stimulated H(2)O(2) production by rat heart mitochondria. The enhancement of H(2)O(2) generation in antimycin-supplemented mitochondria and the increased O(2) uptake of the State 4-to-State 3 transition showed similar protophore, ionophore and Ca(2+) concentration dependencies. Thenoyltrifluoroacetone and N-bromosuccinimide, which inhibit succinate-ubiquinone reductase activity, also decreased mitochondrial H(2)O(2) production. Addition of cyanide to antimycin-supplemented beef heart submitochondrial particles inhibited the generation of O(2) (-), the precursor of mitochondrial H(2)O(2). This effect was parallel to the increase in cytochrome c reduction and it is interpreted as indicating the necessity of cytochrome c(1) (3+) to oxidize ubiquinol to ubisemiquinone, whose autoxidation yields O(2) (-). The effect of protophores, ionophores and Ca(2+) is analysed in relation to the propositions of a cyclic mechanism for the interaction of ubiquinone with succinate dehydrogenase and cytochromes b and c(1) [Wikstrom & Berden (1972) Biochim. Biophys. Acta283, 403-420; Mitchell (1976) J. Theor. Biol.62, 337-367]. A collapse in membrane potential, increasing the rate of ubisemiquinone formation and O(2) (-) production, is proposed as the molecular mechanism for the enhancement of H(2)O(2) formation rates observed on addition of protophores, ionophores and Ca(2+).

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Antimycin A / pharmacology
  • Bromosuccinimide / pharmacology
  • Calcium / pharmacology
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / pharmacology*
  • Columbidae
  • Hydrogen Peroxide / metabolism*
  • In Vitro Techniques
  • Ionophores / pharmacology*
  • Mitochondria, Heart / drug effects
  • Mitochondria, Heart / metabolism*
  • Nitriles / pharmacology*
  • Potassium Cyanide / pharmacology
  • Rats
  • Thenoyltrifluoroacetone / pharmacology


  • Ionophores
  • Nitriles
  • Thenoyltrifluoroacetone
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
  • Antimycin A
  • Adenosine Triphosphate
  • Hydrogen Peroxide
  • Bromosuccinimide
  • Potassium Cyanide
  • Calcium