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3,4-Dihydroxyphenylacetic acid (DOPAC) is a metabolite of the neurotransmitter dopamine. Dopamine can be metabolized into one of three substances. One such substance is DOPAC. Another is 3-methoxytyramine (3-MT). Both of these substances are degraded to form homovanillic acid (HVA). Both degradations involve the enzymes monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT), albeit in reverse order: MAO catalyzes dopamine to DOPAC, and COMT catalyzes DOPAC to HVA; whereas COMT catalyzes dopamine to 3-MT and MAO catalyzes 3-MT to HVA. The third metabolic end-product of dopamine is norepinephrine (noradrenaline).
DOPAC can be oxidized by hydrogen peroxide, leading to the formation of toxic metabolites which destroy dopamine storage vesicles in the substantia nigra. This may contribute to the failure of levodopa treatment of Parkinson's disease. A MAO-B inhibitor such as selegiline or rasagiline can prevent this from happening.
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beige to light brown crystalline powder

3,4-Dihydroxyphenylacetic Acid is a metabolite of Dopamine (D533782).

ChEBI: (3,4-dihydroxyphenyl)acetic acid is a dihydroxyphenylacetic acid having the two hydroxy substituents located at the 3- and 4-positions. It is a metabolite of dopamine. It has a role as a human metabolite. It is a dihydroxyphenylacetic acid and a member of catechols. It is functionally related to a phenylacetic acid. It is a conjugate acid of a (3,4-dihydroxyphenyl)acetate.