Electron transfer from reduced cytochrome c to molecular oxygen Authored: Jassal, B, 2005-06-28 15:06:45 Complex IV (cytochrome oxidase) contains the hemeprotein cytochrome a and a3. It also contains copper atoms which undergo a transition from Cu+ to Cu2+ during the transfer of electrons through the complex to molecular oxygen. A bimetallic centre containing a copper atom and a heme-linked iron protein binds oxygen after 4 electrons have been picked up. Water, the final product of oxygen reduction, is then released. Oxygen is the final electron acceptor in the respiratory chain. The overall reaction can be summed as below:<br><b>4Cyt c</b>_(red.) + <b>12H⁺</b>_in + <b>O₂</b> -> <b>4Cyt c</b>_(ox.) + <b>2H₂O</b> + <b>8H⁺</b>_out<br><br>Four protons are taken up from the matrix side of the membrane to form the water (scalar protons). Wikstrom (1977) suggests 4 protons are additionally transferred out from the matrix to the intermembrane space. EC Number: 1.9.3.1 GENE ONTOLOGYGO:0006123 Pubmed11340051 Pubmed15223 Pubmed7979252 Reactome Database ID Release 43163214 Reactome, http://www.reactome.org ReactomeREACT_6149 has a Stoichiometric coefficient of 12 has a Stoichiometric coefficient of 2 has a Stoichiometric coefficient of 4 has a Stoichiometric coefficient of 8 Cytochrome c-Fe3+ Cytochrome c-Fe2+