Pulse-radiolytic investigations of catechols and catecholamines. II. Reactions of Tiron with oxygen radical species.
Transient spectra and kinetic data of Tiron (1,2-dihydroxybenzene-3,5-disulphonic acid) are reported, obtained after pulse-radiolytic oxidation by hydroxyl radicals (.OH), superoxide anions (O-2) or a combination of both oxygen radicals. The rate constant with .OH radicals was determined at 1.0.10(9) M-1.s-1. Contrary to a previous report (Greenstock, C.L. and Miller, R.W. (1975) Biochim. Biophys. Acta 396, 11--16), the rate constant with O-2 of 1.0.10(7) M-1.s-1 is lower by one order of magnitude; also the semiquinone absorbs at 300 nm rather than at 400 nm. The ratio of the rate constants with .OH and O-2 of 100 again demonstrates that any oxidation reaction by the latter radical is unspecific due to the more efficient reaction of .OH radicals, leading to the same products with catechol compounds.
D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D001557:Benzenesulfonates; D002625:Chemistry, Organic; D006878:Hydroxides; D055601:Organic Chemistry Phenomena; D010100:Oxygen; D011675:Pulse Radiolysis; D013057:Spectrum Analysis; D013481:Superoxides
D001557:Benzenesulfonates; D006878:Hydroxides; D013481:Superoxides; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D010100:Oxygen