Dopaquinone

Part of speech: noun

Definitions

1. A reactive compound formed during the oxidation of dopamine that plays a role in melanin production in the body
2. An intermediary substance in the biosynthesis of pigments where dopamine undergoes oxidation, contributing to hair and skin color
3. A molecular product of dopamine that is involved in the synthesis of melanins and has implications in neurological activities

Etymology: Dopaquinone is a chemist's coinage built from parts that each carry their own history. "Dopa" is an abbreviation of 3,4-dihydroxyphenylalanine, the amino acid that the body converts into dopamine, and the name was shortened in the twentieth century from that long chemical title. The "-quinone" ending marks a class of compounds called quinones, a name coined in the nineteenth century for oxidised aromatic molecules, with the suffix "-one" from ketone. Put together, dopaquinone names the quinone formed when dopa is oxidised. It matters in biology because this oxidation is an early step in melanin production. The enzyme tyrosinase converts dopa into dopaquinone, which then undergoes a series of further reactions that eventually yield the dark pigments in skin, hair and eyes. The term therefore sits at the junction of pigment chemistry and neurochemistry, since the same precursor family supplies both melanin and dopamine.