The mitochondrial generation of hydrogen peroxide. General properties and effect of hyperbaric oxygen

The present paper reports on some general properties of the mitochondrial generation of H202, namely: the substrate specificity; the effect of the antibiotic antimycin A and the dependence of its effect on the energy-state of the mitochondrial membranes; the effect of ubiquinone extraction and its reincorporation on the rates of formation of H202; the pH dependence; the dependence of formation of H202 on the partial pressure of02 in the hyperbaric region

Alberto Boveris; Britton Chance

2015

Scholarcy highlights

  • Antimycin A exerts a very pronounced effect in enhancing H202 production in pigeon heart mitochondria; 0.26nmol ofantimycin A/mg of protein and the addition of an uncoupler are required for maximal H202 formation
  • The present paper reports on some general properties of the mitochondrial generation of H202, namely: the substrate specificity; the effect of the antibiotic antimycin A and the dependence of its effect on the energy-state of the mitochondrial membranes; the effect of ubiquinone extraction and its reincorporation on the rates of formation of H202; the pH dependence; the dependence of formation of H202 on the partial pressure of02 in the hyperbaric region
  • Treated pigeon heart mitochondria were suspended in the reaction medium described in Fig. 1 at a concentration of 0.03mg of protein/ml and supplemented with1.4 pM-cytochrome c peroxidase, 6mM-succinate and 0.3,.LM-antimycin A. *, Ubiquinone-10 incorporated; *, ubiquinone-3 incorporated
  • Ubiquinone-depleted pigeon heart mitochondria supplemented with succinate and antimycin A generate H202 at a rate of about 0.26nmol/min per mg of protein
  • Mitochondria isolated from pigeon heart, rat liver, rat and ox heart, rat kidney, yeast, Ascaris muscle and Crithidia fasciculata have been shown as active sources ofH202
  • The evidence that palmitoylcarnitine does not increase generation of H202 when added to succinate-supplemented mitochondria, along with the fact that succinate does not reduce the flavoproteins of fatty acid oxidation, would indicate the existence of a common rate-limiting step operating with both substrates

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