Aralkylamine N-acetyltransferase

Aralkylamine N-acetyltransferase (AANAT) is an enzyme that is involved in the biochemical process of melatonin synthesis. It is a key regulator in the production of melatonin, a hormone that plays a crucial role in regulating the circadian rhythm in many organisms, including humans.

Function

Aralkylamine N-acetyltransferase is responsible for the acetylation of serotonin into N-acetylserotonin, the immediate precursor of melatonin. This reaction is the penultimate step in the synthesis of melatonin from tryptophan. The enzyme is found in the pineal gland, and its activity is regulated by a circadian rhythm, with the highest levels occurring at night.

Structure

The human AANAT enzyme is a monomer composed of 207 amino acids. It has a molecular weight of approximately 23 kDa. The enzyme contains a conserved acetyl-CoA binding site and a substrate binding site, which are crucial for its function.

Clinical significance

Alterations in the function of AANAT can lead to a variety of disorders, including sleep disorders, mood disorders, and certain types of cancer. For example, low levels of AANAT and melatonin have been associated with insomnia and depression. In addition, some studies have suggested that AANAT may play a role in the development of breast cancer and prostate cancer, possibly due to its role in regulating melatonin levels.

See also

• Melatonin
• Serotonin
• Pineal gland
• Circadian rhythm