Nitric oxide interacts with mitochondrial complex III producing antimycin-like effects

These results show that NO interacts with ubiquinone-cytochrome b area producing antimycin-like effects

Darío E. Iglesias; Silvina S. Bombicino; Laura B. Valdez; Alberto Boveris

2015

Scholarcy highlights

  • H2O2 production was increased by 72–74% when heart coupled mitochondria were exposed to 500 μM GSNO or 30 μM SPER-NO
  • submitochondrial particles incubated in the presence of succinate showed an EPR signal compatible with a stable semiquinone
  • This EPR signal was increased by antimycin and by GSNO and SPER-NO. These signals were not modified under N2 atmosphere, indicating that they are not a consequence to the effect of NOx species on complex III area
  • These results show that NO interacts with ubiquinone-cytochrome b area producing antimycin-like effects
  • Complex II-III activity was decreased when SMP were incubated with l-arginine and mtNOS cofactors, indicating that this effect is produced by endogenous NO
  • This behaviour comprises the inhibition of electron transfer, the interruption of the oxidation of cytochromes b, and the enhancement ofss which, in turn, leads to an increase in O2- and H2O2 mitochondrial production rates

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