Mitochondrial electron transport chain complex I, II, III, IV, and V proteins (ETC complexes I-V (or Complex I, II, III, IV, V))

The mitochondrial electron transport chain comprises five major protein complexes (I-V), embedded in the inner membrane, that work together to oxidize electron donors (NADH, FADH2), transport electrons through a series of redox reactions, pump protons to create an electrochemical gradient, and synthesize ATP from ADP and inorganic phosphate via ATP synthase (complex V). Complexes I-IV transfer electrons and pump protons, while complex V uses the proton gradient to drive ATP synthesis. Dysfunction or inhibition of these complexes can result in severe metabolic and degenerative diseases, and they are targets for several drugs and toxins.

Other names

Complex I: NADH:ubiquinone oxidoreductaseNADH dehydrogenaseComplex II: Succinate dehydrogenasesuccinate:ubiquinone oxidoreductaseComplex III: Cytochrome bc1 complexubiquinol:cytochrome c oxidoreductaseComplex IV: Cytochrome c oxidaseComplex V: ATP synthaseF1F0-ATP synthaseOxidative phosphorylation complexesmitochondrial respiratory complexesETC proteins

Inhibition of electron transfer Disruption of proton gradient (uncoupling) Inhibition of ATP synthesis Generation of reactive oxygen species (ROS)