Turrens 1982 Arch Biochem Biophys
| Turrens JF, Freeman BA, Crapo JD (1982) Hyperoxia increases H2O2 release by lung mitochondria and microsomes. Arch Biochem Biophys 217:411-21. |
Turrens JF, Freeman BA, Crapo JD (1982) Arch Biochem Biophys
Abstract: Hyperoxia increased H2O2 release by lung mitochondria. A 10-fold increase in the rate of H2O2 production was observed when oxygen concentration increased from 21 to 100%. The rate of H2O2 release increased linearly from 0 to 60% oxygen. Above 60% oxygen, the rate of H2O2 release increased dramatically up to 0.19 ± 0.03 nmol · min−1 · mg protein−1 at 100% oxygen. The same effect was observed when mitochondria were supplemented with malate + malonate + glutamanate in the presence of rotenone or when endogenous substrates were oxidized by rotenone-supplemented particles. The three antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase) were present in the mitochondrial fraction obtained from porcine lungs. The effect of oxygen concentration on extramitochondrial H2O2 release may be the consequence of a sufficient increase in the rate of intramitochondrial H2O2 production to overwhelm H2O2 scavenging by intramitochondrial peroxidases. Hydrogen peroxide formation by lung microsomes supplemented with NADPH increased linearly with oxygen concentration from 0.91 ± 0.16 at 21% to 1.6 ± 0.3 nmol · min−1 · mg protein−1 at 100% oxygen. When supplemented with NADH, microsomes produced H2O2 at rates that were about half of those with NADPH, at all oxygen concentrations. From these results, it was estimated that mitochondria can produce 2.9 nmol H2O2/g tissue while microsomes produce 19.7 nmol H2O2/g tissue, when exposed to 100% oxygen. This suggests that the enhanced release of H2O2 by hyperoxic mitochondria and microsomes may be responsible, in part, for the cellular damage observed in lungs of animals breathing oxygen concentrations of 60% or greater.
Cited by
- Komlódi T, Gnaiger E (2022) Discrepancy on oxygen dependence of mitochondrial ROS production - review. MitoFit Preprints 2022 (in prep).
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