title: Hydroxyl radical attack on dopamine.
abstract: Hydroxyl radicals were generated in the presence of 1 mM dopamine (3,4-dihydroxyphenylethylamine) at pH 7.2 (50 mM phosphate buffer) by the following two mechanisms: 1) a classic Fenton-type reaction between hydrogen peroxide and a ferrous chelate (ferrous diethylenetriaminepentaacetate) and 2) the cyclical redox reactions of iron-EDTA/ascorbate. Three ring-monohydroxylated products of dopamine were detected by high performance liquid chromatography with electrochemical detection: 2-hydroxydopamine, 5-hydroxydopamine, and 6-hydroxydopamine in an approximate ratio of 3:2:1. Scavengers of hydroxyl radicals (dimethyl sulfoxide, mannitol, ethanol) suppressed the yields of products in a concentration-dependent manner. The formation of nonphysiologic hydroxylated forms of dopamine can provide a probe for the formation of hydroxyl radicals in dopamine neurons.
mesh_terms: D001205:Ascorbic Acid; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine; D004492:Edetic Acid; D006878:Hydroxides; D006892:Hydroxydopamines; D017665:Hydroxyl Radical; D016627:Oxidopamine
chemical_list: D006878:Hydroxides; D006892:Hydroxydopamines; C027802:5-hydroxydopamine; D017665:Hydroxyl Radical; D016627:Oxidopamine; D004492:Edetic Acid; D001205:Ascorbic Acid; D004298:Dopamine