Spin trapping of radicals formed during radiolysis of aqueous solutions. Direct electron spin resonance observations

Abstract

Can. J. Chem. 54, 275 (1976). It is shown that e,,,,, He, and OH formed by the radiolysis of water by 3 MeV electrons are trapped by nitroso and nitrone compounds to give nitroxides with well defined esr spectra. Three spin trapping agents were used, nitroso-t-butane, phenyl-t-butyl nitrone, and 5,s'-dimethyl pyrroline-I-oxide. The latter was shown to be an excellent con~pound for these studies. Complications due to the instability of some of the nitroxides were overcome by coupling the electron accelerator to the esr spectron~eter to permit direct observation of the spectra. On a montrC que les e,,,,,, Ha, et OH formts par radiolyse de I'eau par des Clectrons B 3 MeV sont captCs par des composes nitroso et nitrone et conduisent B des nitroxydes avec des spectres rpe bien dtfinis. On a utilise trois agents de piCgeage; L e nitroso t-butane, la phtnyl t-butyl nitrone et la dimethyl-5,5' pyrroline oxyde-I. On a n~o n t r i que ce dernier composC est excellent pour ces ttudes. On a CliminC les con~plications dues a I'instabilitC de q~~elques nitroxydes en couplant directement I'acctICrateur d'Clectron au spectromktre de rpe pour permettre une observation directe du spectre.[Traduit par le journal]

EPR investigation of the role of B10 phenylalanine in neuroglobin — Evidence that B10Phe mediates structural changes in the heme region upon disulfide-bridge formation

“…6d). Instead, the well-known fourline EPR spectrum of the DMPO-OH• adduct (g = 2.005 and a nitrogen and proton hyperfine coupling of 14.8 G [34,35] is observed). This indicates the trapping of •OH radicals by the spin trap.…”

Reaction of Human Myoglobin and Peroxynitrite: Characterizing Biomarkers for Myoglobin-Derived Oxidative Stress

“…In the absence of protein, a weak signal was obtained with A N ϭ 1.51 Ϯ 0.03 and A ␤ H ϭ 1.45 Ϯ 0.04 mT (mean Ϯ SD, n ϭ 3), consistent with the hydroxyl radical-adduct of DMPO (Fig. 1C) (25). No signal was detected in mixtures of DMPO and protein(s) alone (e.g., Fig.…”

Estimation of Relative Reaction Rate of Hydroxy Radical with Poly-hydroxy Benzenes: ESR Spin Trapping Combined with UV-A Photolysis

“…The 1:2:2:1 quartet pattern shows the hyperfine coupling of 1.5 mT, the same value as that of DMPO-OH reported previously. 12 The yield of DMPO-OH decreased with an increase in hydroquinone concentration. Such a negative correlation between the DMPO-OH yield and the concentration of hydroquinone was not observed when the molar ratio of the hydrogen peroxide versus DMPO was unity (500 μM) and the U-340 filter was used during the irradiation.…”