Characterization of peroxidative oxidation products of dopamine by mass spectrometry

Michael B. Mattammal, Randy Strong, Edward White V, Fong Fu Hsu

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13 Scopus citations


We characterized three cytotoxic products, namely dopaminochrome (2,3-dihydro-1H-indole-5,6-dione), 2-(3,4-dihydroxyphenyl)-1-nitroethane and 2-(3,4,6-trihydroxyphenyl)-1-nitroethane. The compounds were separated from the incubation of dopamine (3,4-dihydroxyphenethylamine) with horseradish peroxidase which mimics the peroxidative activity of Prostaglandin H synthase. Incubation of 2-(3,4,6-trihydroxyphenyl)-1-nitroethane with NADPH-cytochrome c reductase led to the formation of 6-hydroxydopamine, a known neurotoxin. Several adducts were also isolated in this study. Oxidation of dopamine in the presence of N-acetylcysteine yielded a thioether conjugate namely, 5-S-(N-acetylcysteinyl)-3,4-dihydroxyphenethylamine. Reaction of the partially purified dopaminochrome with N-acetylcysteine permitted the isolation of another thioether conjugate which was tentatively identified as 7-S-(N-acetylcysteinyl)-5,6-dihydroxyindole. We also isolated the one-to-one condensation products of malonaldehyde with dopamine, norepinephrine and serotonin. The identities of these products were established by chemical synthesis and various mass spectrometric techniques.

Original languageEnglish
Pages (from-to)21-30
Number of pages10
JournalJournal of Chromatography B: Biomedical Sciences and Applications
Issue number1
StatePublished - Aug 5 1994


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