Co-enzyme

A coenzyme is a molecule which helps the functioning and activity of an enzyme by binding and therefore activating it to form the holoenzyme^[1]. Coenzymes are nonpolypeptide small molecules or ions that are bound in the active site, and can be chemically modified during the reaction so need to be replaced or regenerated afterwards^[2]. Examples include NAD⁺ (nicotinamide adenine dinucleotide), FAD (flavin adenine dinucleotide) and haem groups that bind oxygen in haemoglobin^[3].

References

1. ↑ Medicine Net, Coenzymes, https://www.medicinenet.com/script/main/art.asp?articlekey=13153
2. ↑ Lodish H, Kaiser CA, Bretcher A, Amon A, Berk A, Kneger M, Ploegh H, Scott MP. Molecular Cell Biology. 7th Ed, New York: W.H. Freeman and Company. 2013.
3. ↑ Lodish H, Kaiser CA, Bretcher A, Amon A, Berk A, Kneger M, Ploegh H, Scott MP. Molecular Cell Biology. 7th Ed, New York: W.H. Freeman and Company. 2013.