Catechol-O-methyltransferase

Catechol-O-methyltransferase (COMT) is an enzyme that plays a significant role in the metabolism of catecholamines in the human body. Catecholamines include neurotransmitters such as dopamine, epinephrine, and norepinephrine. COMT is encoded by the COMT gene.

Function[edit | edit source]

COMT is involved in the inactivation of the catecholamine transmitters. The enzyme introduces a methyl group to the catecholamine, which is donated by S-adenosyl methionine (SAM). Any compound having a catechol structure, like catecholestrogens and catechol-containing flavonoids, are substrates of COMT.

Structure[edit | edit source]

The COMT gene is located on the 22nd chromosome (22q11.21). This gene produces two forms of the enzyme - soluble (S-COMT) and membrane-bound (MB-COMT). The difference between these two forms is that MB-COMT has an extra 50 amino acids at the N-terminus.

Clinical significance[edit | edit source]

Variations and mutations in the COMT gene can affect the function of the enzyme and have been linked to a variety of neuropsychiatric disorders, including schizophrenia, depression, and bipolar disorder. COMT inhibitors, like entacapone and tolcapone, are used in the treatment of Parkinson's disease.

Pharmacology[edit | edit source]

COMT plays a significant role in areas of the brain where dopamine is abundant, particularly in the prefrontal cortex. COMT inhibitors, which inhibit the action of the enzyme, are used to prolong the effect of levodopa therapy in Parkinson's disease.

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Mechanism of COMT