Cytochromes

Cytochromes are a group of heme-containing enzymes involved in electron transport and oxidation-reduction reactions. They are found in the mitochondria of eukaryotic cells, and in the plasma membrane of prokaryotes.

Function

Cytochromes function as electron carriers in the electron transport chain, a series of reactions that ultimately generates adenosine triphosphate (ATP) through the process of oxidative phosphorylation. They are crucial for the production of energy in cells.

Types

There are several types of cytochromes, including cytochrome a, cytochrome b, and cytochrome c. Each type has a different role in the electron transport chain.

Cytochrome a

Cytochrome a is part of Complex IV (also known as cytochrome c oxidase) of the electron transport chain. It helps to transfer electrons from cytochrome c to oxygen, the final electron acceptor.

Cytochrome b

Cytochrome b is part of Complex III (also known as cytochrome bc1 complex or ubiquinol-cytochrome c reductase) of the electron transport chain. It helps to transfer electrons from ubiquinol to cytochrome c.

Cytochrome c

Cytochrome c is a small, soluble protein that shuttles electrons between Complex III and Complex IV of the electron transport chain.

Clinical significance

Mutations in the genes encoding cytochromes can lead to a variety of diseases, including mitochondrial diseases and certain types of cancer. For example, mutations in the gene encoding cytochrome c can lead to apoptosis, or programmed cell death, which can contribute to the development of cancer.

See also

• Electron transport chain
• Oxidative phosphorylation
• Mitochondria
• Enzyme

References

Cytochromes Resources
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