Question

Which complex is formed by Cyt a and Cyt a3?

Answer 1

Complex IV :

1. Complex IV or cytochrome c oxidase is formed by cyt a and cyt a3.
2. Complex IV is involved in the electron transport system (ETS).
3. Complex IV or Cytochrome c Oxidase (COX) is the last electron acceptor of the respiratory chain, involved in the reduction of O2 to H2O.
4. The terminal oxidation is the last step of the electron transport chain in which electrons from cytochrome c are transferred via cyt a and cyt a3 to oxygen.
5. The reaction is catalyzed by cytochrome oxidase enzyme which is tightly bound to the inner mitochondrial membrane.
6. It contains inseparable cyt a and cyt a3 components and also some polypeptides that contain two copper ions.
7. Both iron and copper undergo reversible changes in their oxidation states during electron transport by cytochrome oxidase.