Serotonin N-acetyl transferase

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Identifiers
EC number	2.3.1.87
CAS number	9037-14-3
Alt. names
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway

Serotonin N-acetyltransferase (also known as arylalkylamine N-acetyltransferase or AANAT) is an enzyme that plays a crucial role in the biosynthesis of melatonin from serotonin. It is primarily found in the pineal gland, where it catalyzes the transfer of an acetyl group from acetyl-CoA to serotonin, forming N-acetylserotonin, an immediate precursor of melatonin.

Function

Serotonin N-acetyltransferase is the rate-limiting enzyme in the production of melatonin. The activity of this enzyme is influenced by the light-dark cycle, being higher during the night, which leads to increased melatonin synthesis when it is dark. This regulation is a critical component of the circadian rhythms in mammals.

Structure

The enzyme is encoded by the AANAT gene. The structure of Serotonin N-acetyltransferase includes a domain that binds acetyl-CoA and a separate domain that binds serotonin. This arrangement facilitates the efficient transfer of an acetyl group to serotonin.

Clinical Significance

Alterations in the expression or function of Serotonin N-acetyltransferase can affect sleep patterns and mood, and have been implicated in various sleep disorders and mood disorders. Additionally, because of its role in regulating melatonin levels, it is also potentially involved in the regulation of reproductive hormones and seasonal breeding.

See Also

• Melatonin
• Pineal gland
• Circadian rhythm
• Sleep disorder