CoQ-cytochrome c oxidoreductase

Complex III (CoQ cytochrome c oxidoreductase) transfers electrons from CoQ to cytochrome c, through a sequence of cytochrome and iron-sulfur cofactors. Here, Alf for the couple CoQ/cytochrome c is 0.19 V, corresponding to a AG° of —36.7 kJ/mol, again enough to power the synthesis of an ATP molecule and to ensure that protons are pumped across the inner mitochondrial membrane. 

Figure 6-1 The electron transfer chain of Paracoccus denitrificans (adapted from [5]). CoQ-cytochrome c oxidoreductase and cytochrome c oxidase are located in the cytoplasmic membrane and linked by the membrane-bound cytochrome C552. Cytochrome C550 and cytochrome c peroxidase are located in the periplasmic region P, periplasm M, cytoplasmic membrane C, cytoplasm.

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