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NEAR UV‐INDUCED FREE RADICALS IN OCULAR LENS, STUDIED BY ESR AND SPIN TRAPPING
Author(s) -
MURAKAMI JUNKO,
OKAZAKI MASAHARU,
SHIGA TAKESHI
Publication year - 1989
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1989.tb09196.x
Subject(s) - spin trapping , chemistry , adduct , photochemistry , radical , photodissociation , electron paramagnetic resonance , protonation , irradiation , reagent , solvated electron , tryptophan , ionization , nuclear magnetic resonance , radiolysis , organic chemistry , ion , biochemistry , physics , amino acid , nuclear physics
— An electron spin resonance (ESR) study on UV‐photolysis of human and canine lens nuclei was carried out at room temperature. (1) At least two kinds of free radical signals, a narrow signal and a broad one, were detected at around g=2.004. The latter is similar to that observed upon irradiation of a model solution containing both tryptophan and cysteine. (2) Two spin adducts were detected upon irradiation of canine lens in the presence of a spin trapping reagent (DMPO, 5,5‐dimethyl‐1‐pyrroline N‐oxide), i.e. a spin adduct of sulphur‐centered radical (most likely glutathione thiyl radical) and the protonated adduct of solvated electron (presumably due to photo‐ionization of tryptophan). (3) A tentative and simplified reaction mechanism of UV‐induced damage is discussed on the basis of these observations.