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SUPEROXIDE DISMUTASE AS AN AMPLIFIER OF THE CHEMICAL REACTIVITY OF PORPHYRIN RADICAL‐CATIONS
Author(s) -
Bazin M.,
Patterson L. K.,
RonfardHaret J. C.,
Santus R.
Publication year - 1988
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.1751-1097.1988.tb02803.x
Subject(s) - porphyrin , chemistry , photochemistry , superoxide dismutase , radiolysis , flash photolysis , aqueous solution , reactivity (psychology) , radical ion , hydroxyl radical , superoxide radical , radical , organic chemistry , reaction rate constant , kinetics , antioxidant , ion , medicine , physics , alternative medicine , pathology , quantum mechanics
— Porphyrin radical‐cations have been produced using laser flash photolysis via oxidation of the porphyrin triplets by metronidazole. This radical‐cation reacts with OJ as shown by its increased half‐life in the presence of native superoxide dismutase. Comparable results are obtained when porphyrin radical‐cations are formed by Br 2 ‐ O 2 ‐ oxidation of porphyrins produced in pulse radiolysis of oxygen‐saturated aqueous solutions containing 20 mM Br ‐ O ‐ . These results provide an explanation for the enhancement by superoxide dismutase of the photosensitizing capacity of porphyrins in the presence of electrophilic nitroimidazoles (Bazin and Santus, 1986). They may also apply to porphyrin radical‐cations formed by monophotonic or biphotonic photoionization processes.