respiratory chain complex IV

Definition

Target type: cellularcomponent

A part of the respiratory chain, containing the 13 polypeptide subunits of cytochrome c oxidase, including cytochrome a and cytochrome a3. Catalyzes the oxidation of reduced cytochrome c by dioxygen (O2). [ISBN:0198547684]

Respiratory chain complex IV, also known as cytochrome c oxidase, is a large transmembrane protein complex found in the inner mitochondrial membrane. This complex is the final electron acceptor in the mitochondrial electron transport chain, transferring electrons from cytochrome c to molecular oxygen, reducing it to water. It plays a crucial role in oxidative phosphorylation, the process by which ATP is generated using the energy released from the oxidation of fuel molecules. Complex IV is composed of 13 subunits in mammals, including three core subunits (COX1, COX2, and COX3) encoded by mitochondrial DNA and 10 nuclear encoded subunits. COX1 and COX2 contain heme a and heme a3, which are essential for electron transfer, while COX3 binds copper ions, forming the CuA and CuB centers. The enzyme complex also contains two binuclear copper centers (CuA and CuB) and a heme a3-CuB binuclear center. The CuA center receives electrons from cytochrome c, while the heme a3-CuB center transfers them to molecular oxygen. This process involves a complex series of proton pumping and electron transfer steps. The overall structure of complex IV is a dimer with two monomers, each containing the active site for oxygen reduction. The two monomers interact with each other through hydrophobic and electrostatic interactions, forming a stable and functional complex. Complex IV is essential for cellular respiration and plays a critical role in maintaining energy homeostasis in cells. Mutations in complex IV can lead to mitochondrial diseases, characterized by impaired oxidative phosphorylation and reduced ATP production.'
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Proteins (2)

Compounds (7)