Cytochrome C

Cytochrome C oxidase is a protein that is found in the inner membrane of the mitochondria as an integral transmembrane protein. It is the final unit in the electron transport chain. Its structure contains 14 subunits and two hemes. The second photo below shows the structure.

The Cytochrome C oxidase functions in many ways. First, it transfers 4 protons at a time into the inner membrane space to establish the proton gradient. It then takes the electrons and transfers them to the oxygen molecule to start the formation molecular oxygen. It also binds the protons that travel through the ATP synthase to that oxygen molecule to make 2 complete molecular oxygens.

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References:

• http://www.sciencemag.org/content/280/5370/1712/F1.medium.gif
• http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Cmplx4.PNG/300px-Cmplx4.PNG