Mitochondrial respiratory chain and thioredoxin reductase regulate intermembrane Cu,Zn-superoxide dismutase activity: implications for mitochondrial energy metabolism and apoptosis

The present study aimed to identify biochemical pathways implicated in the regulation of intermembrane space SOD1 activity and to assess the impact of its functional state on key mitochondrial events

Pedro IƱarrea


Scholarcy highlights

  • Recent studies on the subcellular distribution of SOD demonstrated that SOD1 is localized in the cytosol, and in the mitochondrial intermembrane space of rat liver and yeast
  • In order to determine the biochemical processes involved in the activation of IMS SOD1, a series of experiments were conducted with intact mitochondria and the purified inactive enzyme
  • The findings of the present study suggest that the mitochondrial respiratory chain and thioredoxin reductase-1 regulate IMS SOD1 activity
  • In order to elucidate the biochemical pathways involved in reversible activation of IMS SOD1, a series of experiments were conducted with intact mitochondria and with purified SOD1 reduced by DTT to an inactive state
  • H2O2 transiently activated SOD1 in intact mitochondria, it did not affect the activity of the reduced enzyme once it was purified from the IMS, suggesting that additional mitochondrial component(s) are necessary to catalyse the intra-subunit disulfide-bond formation
  • In spite of localization of the peroxiredoxin III in the mitochondrial matrix and in the IMS, our findings suggest that peroxiredoxin III is not implicated in the activation of SOD1
  • These findings suggest that H2O2, superoxide and thioredoxin reductase-1 reversibly regulate intermembrane space SOD1 activity, and that the enzyme is implicated in protecting vital mitochondrial functions

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