What question did this study set out to answer?

To elucidate the kinetic and molecular mechanisms governing superoxide production by mitochondrial complex I.

May 9, 2006Proceedings of the National Academy of SciencesOpen Access

The mechanism of superoxide production by NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria

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Authors

LKLothar KußmaulBoehringer Ingelheim (Germany)JHJudy HirstUniversity of Cambridge

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Implication

Biochemical analysis reveals that fully reduced flavin generates superoxide in bovine heart mitochondrial complex I, indicating that NADH and NAD+ ratios regulate cellular oxidative stress.

Key Points

To elucidate the kinetic and molecular mechanisms governing superoxide production by mitochondrial complex I.
Purified complex I isolated from bovine heart mitochondria.
Conducted redox titrations and electron paramagnetic resonance spectroscopy to identify the specific site of oxygen reduction in the absence of a proton motive force.
Complex I produces predominantly superoxide instead of hydrogen peroxide, with iron-sulfur clusters and the flavin radical ruled out as direct electron donors to oxygen.
Superoxide generation occurs via single-electron transfer from fully reduced flavin to oxygen within an unoccupied active site.
The rate of superoxide formation is governed by a bimolecular reaction dependent on the preequilibrium set by the concentrations and ratio of NADH to NAD+.

Cite This Study

Kußmaul et al. (2006) studied this question.

synapsesocial.com/papers/6a0f3b1ea7a2fed64abdd6e2 https://doi.org/10.1073/pnas.0510977103

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Implication

Biochemical analysis reveals that fully reduced flavin generates superoxide in bovine heart mitochondrial complex I, indicating that NADH and NAD+ ratios regulate cellular oxidative stress.

The mechanism of superoxide production by NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria

Discussion

Member takes

Implication

Key Points

Cite This Study

The mechanism of superoxide production by NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria

Discussion

Member takes

Implication

Key Points

Cite This Study

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