title: [Antioxidants as aromatic amino acid oxidation products].
abstract: The accumulation of UV photolysis products of amino acids tyrosine and tryptophan, which possess an antioxidant activity, has been studied by the method of luminol-activated chemiluminescence. The amount of antioxidant products was judged by the value of the total antioxidant potential of a UV-irradiated solution, the measure of which was the distance between the peaks of the chemiluminescence curve in the system 2,2'-azo-bis(2-amidinopropane)hydrochloride + luminol in a UV-irradiated and an unirradiated samples (induction period, tau(i)). Simultaneously, the absorption and fluorescence spectra of unirradiared and UV-irradiated amino acid solutions were recorded. It was shown that, upon the exposure of a tryptophan solution to radiation, the accumulation of the fluorescent product N-formyl kynurenine (lambda(em) = 325 nm, lambda(max) = 440 nm) occures, and the curve of its accumulation was similar to the curve of growth of tau(i) photoproducts produced during UV-radiation. When a tyrosine solution was irradiated, the main fluorescent product was dityrosine (lambda(em) = 310 nm, lambda(max) = 415 nm). Nevertheless, the dose dependencies of the formation of dityrosine, and the total antioxidant potential (tau(i)) were completely different. It was found that another product of tyrosine UV-photolysis, dioxyphenylalanine, possessed a pronounced antioxidant activity. It was concluded that the main antioxidants produced under UV-irradiation of tryptophan is formyl kynurenine, and under the irradiation of tyrosine, dioxyphenylalanine.
authors.forename: A M
authors.initials: AM
authors.lastname: Polimova
authors.forename: G A
authors.initials: GA
authors.lastname: Vladimirova
authors.forename: E V
authors.initials: EV
authors.lastname: Proskurnina
authors.forename: Iu A
authors.initials: IuA
authors.lastname: Vladimirov
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D010084:Oxidation-Reduction / Q000528:radiation effects; D010782:Photolysis; D014364:Tryptophan / Q000737:chemistry*; D014443:Tyrosine / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D014443:Tyrosine; D014364:Tryptophan