COMT catalyzes the transfer of a methyl group from S-adenosylmethionine（SAM) to catechol substrates such as the neurotransmitters dopamine， epinephrine， and norepinephrine. This O-methylation results in one of the main degradative pathways of the catecholamine transmitters. COMT COMT is located in the postsynaptic neuron and is involved in the metabolism of catechol estrogen drugs used in the treatment of hypertension， asthma， Parkinson disease and the inactivation of catecholamine neurotransmitters though enzymatic degradation. COMT appears in tissues in 2 forms， a soluble form and a membrane-bound form which differ in their N-termini. COMT inhibitors prevent levodopa degradation， increase its availability and are used in the treatment of patients with Parkinson’s disease.
