Cytochrome c oxidase subunit III

Cytochrome c oxidase subunit III (COX3) is a protein that in humans is encoded by the MT-CO3 gene. It is a component of the electron transport chain in mitochondria, which plays a crucial role in cellular respiration.

Function

Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It plays an essential role in the transfer of electrons from cytochrome c to oxygen. This process drives the synthesis of adenosine triphosphate (ATP), the main source of energy in cells. COX3 is one of the three mitochondrial DNA (mtDNA)-encoded subunits of COX.

Structure

The MT-CO3 gene provides instructions for making a protein that is a subunit of the cytochrome c oxidase complex. This complex is a part of the mitochondrial respiratory chain and consists of 13 protein subunits. The MT-CO3 gene is located in mitochondrial DNA, which is found in the mitochondria.

Clinical significance

Mutations in the MT-CO3 gene have been associated with a variety of mitochondrial disorders. These include Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonic epilepsy with ragged-red fibers (MERRF).

See also

• Cytochrome c oxidase
• Mitochondrial DNA
• Electron transport chain
• Cellular respiration