The organosulfur peroxy radical in biological systems: An ESR study using an aminothiol model system

Copeland, Edmund S.

doi:10.1016/0022-2364(75)90158-4

Cited by 3 publications

(5 citation statements)

References 13 publications

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“…One of these labile signals, signal B, was anisotropic with axial symmetry with g1l = 2.033 and go = 2.005. The g values, temperature instability, and power saturation properties of this signal are identical to those previously demonstrated for the alkyl peroxyl free radical, RO0 (25). The presence ofaxial symmetry is also similarly observed for the superoxide free radical, *°2, however, the observed g values are different than those reported for *°2 in aqueous solution.…”

Section: Discussionsupporting

confidence: 81%

“…The observed g values are identical to those of alkyl peroxyl free radicals but also fall within the range of values described for superoxide (25,26). The power saturation behavior of this signal was investigated in samples from postischemic reflowed hearts, and saturation was observed only at high microwave power > 20 mW.…”

Section: Resultssupporting

confidence: 76%

“…This signal was observed to be stable only at very low temperatures < 193°K. Similar power saturation and temperature instability has been observed for the superoxide anion free radical and the alkyl peroxyl free radical (25,26).…”

Section: Resultssupporting

confidence: 74%

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Recombinant superoxide dismutase reduces oxygen free radical concentrations in reperfused myocardium.

et al. 1987

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It has been proposed that oxygen free radicals mediate damage that occurs during postischemic reperfusion. Recombinant human superoxide dismutase (r-h-SOD) has been shown to be effective at reducing reperfusion injury, but it is not known if this infused enzyme actually reduces oxygen free radical concentrations in the myocardial tissue. Electron paramagnetic resonance spectroscopy was used to directly measure the effect of r-h-SOD on free radical concentrations in the postischemic heart. Hearts were freeze clamped at 77°K after 10 min of normothermic global ischemia followed by 10 s of reflow with control perfusate (n = 7) or perfusate containing 60,000 U r-h-SOD (n = 7). The spectra of these hearts exhibited three different signals: signal A isotropic, g = 2.004, identical to the carbon-centered ubiquinone free radical; signal B anisotropic with axial symmetry, g11 = 2.033, gI = 2.005, identical to the oxygen-centered alkyl peroxyl free radical; and the signal C an isotropic triplet, g = 2.000, a. = 24 G, similar to a nitrogencentered free radical such as a peroxyl amine. With r-h-SOD administration the concentration of the oxygen free radical, signal B, was reduced 49% from 6.8±0.3 ,uM to 3.5±0.3 ,M (P < 0.01) and the concentration of the nitrogen free radical, signal C, was reduced 38% from 3.4±0.3 to 2.1±0.3 ;MM (P < 0.01). The concentration of the carbon-centered free radical, signal A, however, was increased 51% from 3.3±0.2 to 5.0±0.2 ,uM (P < 0.01). Identical reperfusion with peroxide-inactivated r-h-SOD did not alter the concentrations of free radicals indicating that the specific enzymatic activity of r-h-SOD is required to decrease the concentrations of reactive oxygen free radicals. Additional measurements performed varying the duration of reflow demonstrate a burst of oxygen free radical generation peaking at 10 s of reperfusion. r-h-SOD entirely abolished this burst. These studies demonstrate that superoxide-derived free radicals are generated during postischemic reperfusion and suggest that the beneficial effect of r-h-SOD is due to its specific enzymatic scavenging of superoxide free radicals.

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Section: Discussionsupporting

confidence: 81%

Section: Resultssupporting

confidence: 76%

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Recombinant superoxide dismutase reduces oxygen free radical concentrations in reperfused myocardium.

et al. 1987

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“…The localization of the unpaired electron on the sulfur atom causes a substantial deviation of the g-factor from the ge and leads to its tensor character. Magnetic parameters of such a center are also determined from the ESR spectra in the usually used 3 cm wave band [55].…”

Section: Identification Of the Paramagnetic Centers Via The 2 MM Bandmentioning

confidence: 99%

“…The unpaired electron in such centers localizes mainly on the O--O fragment, therefore HFS is absent, the values of their g-factors ate close to each other [55], and the identification of PR in the 3 cm ESR spectra is difficult.…”

Section: Identification Of the Paramagnetic Centers Via The 2 MM Bandmentioning

confidence: 99%

Investigation of biological systems by high resolution 2 mm wave band ESR

Krinichnyi

1991

Appl Magn Reson

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The application of the high resolution ESR technique for investigation of various biological systems is shown. The advantages of the technique in the study of structural, conformational and dynamic characteristics are exemplified by spin labeled human serum albumin, egg lysozyme, liposome membranes, inverted micelles, a-chymotrypsin, cotton fiber and cellulose. The polarity of microenvironment and the mechanisms of molecular mobility of the objects under study are determined. The combination of high resolution and saturation transfer techniques is shown to give the detailed analysis of very slow molecular motions in biological objects. Peroxide radicals in biosystems are identified by the ESR spectra of the 2 mm wave band.

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ESR investigations at low temperatures of oxygen radical interaction with rat chromochelatin and metallothioneins

Płonka

Metodiewa

Szymańska³

et al. 1982

Biochemical and Biophysical Research Communications

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The organosulfur peroxy radical in biological systems: An ESR study using an aminothiol model system

Cited by 3 publications

References 13 publications

Recombinant superoxide dismutase reduces oxygen free radical concentrations in reperfused myocardium.

Recombinant superoxide dismutase reduces oxygen free radical concentrations in reperfused myocardium.

Investigation of biological systems by high resolution 2 mm wave band ESR

ESR investigations at low temperatures of oxygen radical interaction with rat chromochelatin and metallothioneins

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