Table of Contents
What does Catechol-O-methyltransferase break down?
This form of the enzyme helps control the levels of certain hormones. In the brain, catechol-O-methyltransferase helps break down certain chemical messengers called neurotransmitters.
What does Catechol-O-methyltransferase do?
Catechol-O-methyltransferase (COMT), an enzyme that is involved in the degradation of catecholamine neurotransmitters (e.g., dopamine, epinephrine, and norepinephrine), can affect executive functions involved in cognitive flexibility, impulse control, abstract thought, and the ability to follow instructions (1, 2, 3).
What is Catechol-O-methyltransferase polymorphism?
Summary. Catechol-O-methyltransferase catalyzes the transfer of a methyl group from S-adenosylmethionine to catecholamines, including the neurotransmitters dopamine, epinephrine, and norepinephrine. This O-methylation results in one of the major degradative pathways of the catecholamine transmitters.
Where are COMT and Mao found?
Either monoamine oxidase A (MAO) or catechol-O-methyltransferase (COMT) can catalyze the first step in catecholamine catabolism. MAO is located on the outer membranes of mitochondria and thus, in brain, is present primarily in nerve terminals and glia.
What does the COMT gene produce?
What is it? The COMT gene provides instructions for making an enzyme called catechol-O-methyltransferase.
How do COMT inhibitors work?
The COMT inhibitors, tolcapone and entacapone, are a new class of Parkinson’s medications. By inhibiting the enzyme catechol-o-methyl-transferase (COMT), they prevent peripheral degradation of levodopa, allowing a higher concentration to cross the blood-brain barrier.
Are COMT and MAO the same?
Catechol-O-methyltransferase (COMT) and/or MAO (monoamine oxidase) further catalyze the metabolism of monoamines. Sympathetic nerves contain only MAO, but adrenal chromaffin cells contain both MAO and COMT. The COMT enzyme is distributed in all organs.
What is COMT genotype?
The COMT gene provides instructions for making an enzyme called catechol-O-methyltransferase. An estimated 20-30% of Caucasians of European ancestry have a COMT gene variation which limits the body’s ability to remove catechols (a specific type of molecule that includes dopamine, norepinephrine, estrogen, etc.)
Why is the catechol O methyltransferase COMT inhibitor added to carbidopa levodopa therapy?
Adding a COMT inhibitor slows the breakdown of levodopa in the body. This allows more of it to get into the brain, thus increasing its effects.
Where do COMT inhibitors act?
COMT are enzymes that break down levodopa, limiting the amount delivered to the brain. COMT inhibitors suppress the activity of COMT enzymes, subsequently extending the window of time in which levodopa is active. This reduces the occurrence of “off” episodes (the time between levodopa doses when motor symptoms recur).
How is tyrosine converted to L-dopa?
L-Dopa can be obtained from L-tyrosine by a hydroxylation reaction catalysed by the enzyme tyrosinase (EC 1.10. 3.1). Such a reaction using immobilized tyrosinase could form the basis of an industrial method because L-tyrosine is cheap.
What is the function of catechol O methyltransferase?
Catechol-O-Methyltransferase (COMT) Gene and Offending Behavior. COMT is an enzyme that facilitates the degradation of active dopamine in the synapse and is expressed in the pyramidal neurons of the prefrontal cortex and hippocampus ( Papaleo et al., 2008 ).
What is the catechol-O-methyltransferase gene?
The catechol-O-methyltransferase (COMT) gene plays a role in degrading dopamine, epinephrine, and norepinephrine, all three of which are neurotransmitters collectively known as the catecholamines ( Winterer & Goldman 2003 ).
What is the substrate of catecholamine?
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. Levodopa, a precursor of catecholamines, is an important substrate of COMT.