Sites of superoxide and hydrogen peroxide production during fatty acid oxidation in rat skeletal muscle mitochondria.

TitleSites of superoxide and hydrogen peroxide production during fatty acid oxidation in rat skeletal muscle mitochondria.
Publication TypeJournal Article
Year of Publication2013
AuthorsPerevoshchikova IV, Quinlan CL, Orr AL, Gerencser AA, Brand MD
JournalFree Radic Biol Med
Date Published2013 Aug
KeywordsAnimals, Electron Transport Complex II, Fatty Acids, Female, Hydrogen Peroxide, Mitochondria, Muscle, Muscle, Skeletal, Oxidation-Reduction, Oxygen Consumption, Palmitoylcarnitine, Rats, Rats, Wistar, Superoxides

H2O2 production by skeletal muscle mitochondria oxidizing palmitoylcarnitine was examined under two conditions: the absence of respiratory chain inhibitors and the presence of myxothiazol to inhibit complex III. Without inhibitors, respiration and H2O2 production were low unless carnitine or malate was added to limit acetyl-CoA accumulation. With palmitoylcarnitine alone, H2O2 production was dominated by complex II (44% from site IIF in the forward reaction); the remainder was mostly from complex I (34%, superoxide from site IF). With added carnitine, H2O2 production was about equally shared between complexes I, II, and III. With added malate, it was 75% from complex III (superoxide from site IIIQo) and 25% from site IF. Thus complex II (site IIF in the forward reaction) is a major source of H2O2 production during oxidation of palmitoylcarnitine ± carnitine. Under the second condition (myxothiazol present to keep ubiquinone reduced), the rates of H2O2 production were highest in the presence of palmitoylcarnitine ± carnitine and were dominated by complex II (site IIF in the reverse reaction). About half the rest was from site IF, but a significant portion, ∼40pmol H2O2·min(-1)·mg protein(-1), was not from complex I, II, or III and was attributed to the proteins of β-oxidation (electron-transferring flavoprotein (ETF) and ETF-ubiquinone oxidoreductase). The maximum rate from the ETF system was ∼200pmol H2O2·min(-1)·mg protein(-1) under conditions of compromised antioxidant defense and reduced ubiquinone pool. Thus complex II and the ETF system both contribute to H2O2 productionduring fatty acid oxidation under appropriate conditions.

Alternate JournalFree Radic. Biol. Med.
PubMed ID23583329
PubMed Central IDPMC3871980
Grant ListR01 AG033542 / AG / NIA NIH HHS / United States
TL1 AG032116 / AG / NIA NIH HHS / United States
R01AG033542 / AG / NIA NIH HHS / United States
TL1AG032116 / AG / NIA NIH HHS / United States