title: Highly site-specific oxygenation of 1-methylhistidine and its analogue with a copper (II)/ascorbate-dependent redox system.
abstract: The reaction of histidine-related materials with copper(II) and ascorbate under physiological conditions has been studied chemically. We discovered that 1-methylimidazole and its analogues, including biological metabolites L-1-methylhistidine and anserine (beta-alanyl-L-1-methylhistidine), exhibited dramatic reactivity with copper(II)/ascorbate. Reaction of copper(II) and ascorbate occurs specifically at the C-2 position of the imidazole ring of L-1-methylhistidine and anserine derivatives with mono-oxygenation to give the 1-methyl-2-imidazolones in good to excellent yields (70-80%). The occurrence of an oxocopper(III) intermediate in the oxidation process of ascorbate is postulated.
authors.affiliation: Department of Food Science and Technology, Nagoya University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Uchida
authors.forename: S
authors.initials: S
authors.lastname: Kawakishi
mesh_terms: D000107:Acetylation; D000861:Anserine; D001205:Ascorbic Acid; D002851:Chromatography, High Pressure Liquid; D003300:Copper; D006639:Histidine / Q000031:analogs & derivatives; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008762:Methylhistidines; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D008762:Methylhistidines; C028120:1-methylhistidine; D006639:Histidine; D003300:Copper; D000861:Anserine; D001205:Ascorbic Acid