Complex III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc1)
Cofactors used
What it does, reaction by reaction
Electron Transport Chain (Complexes I–IV) Energy Metabolism & Cellular Respiration · Inner mitochondrial membrane
QH2 + 2 cytochrome c(Fe3+) + 2 H+matrix → Q + 2 cytochrome c(Fe2+) + 4 H+intermembrane space
Converts Ubiquinol (CoQH2) Cytochrome c(Fe3+) H+ (matrix) into Cytochrome c(Fe2+) H+ (intermembrane space)
› Notes
Required cofactors: cytochromes bL and bH, cytochrome c1, and the Rieske [2Fe–2S] protein. Through the Q cycle, oxidation of two QH2 molecules transfers two electrons to two cytochrome c molecules and results in a net 4 H+ translocated/released to the intermembrane space per electron pair; this is a key proton-pumping step.
Showing all 1 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
No regulation recorded for this enzyme in the source documents.
Recent literature
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