Figure 6.

Major sites of superoxide production from the respiratory chain. The arrows represent the sources of superoxide at different sites in relation to the inner mitochondrial membrane. Blue, CI, NADH-ubiquinone oxidoreductase; yellow, CII, succinate-ubiquinone oxidoreductase; red, CIII, ubiquinol-cytochrome c oxidoreductase; green, CIV, cytochrome oxidase; NDi and NDe, internal and external alternative NAD(P)H dehydrogenases; AOX, alternative oxidase; αGP, glycerol-3-phosphate; ETF, electron transfer flavoprotein; Q, Coenzyme Q (ubiquinone); Cyt C, cytochrome c; (see text for details).