Editing Electron transport chain (section)

====Complex IV====
In [[Complex IV]] ([[cytochrome c oxidase|cytochrome ''c'' oxidase]]; {{EC number|1.9.3.1}}), sometimes called cytochrome AA3, four electrons are removed from four molecules of [[cytochrome c|cytochrome ''c'']] and transferred to molecular oxygen (O{{sub|2}}) and four protons, producing two molecules of water. The complex contains coordinated copper ions and several heme groups. At the same time, eight protons are removed from the mitochondrial matrix (although only four are translocated across the membrane), contributing to the proton gradient. The exact details of proton pumping in Complex IV are still under study.<ref name=":1">{{Cite book|last=Stryer.|title=Biochemistry|publisher=toppan|oclc=785100491}}</ref> [[Cyanide]] is an inhibitor of Complex IV.{{cn|date=January 2025}}