Increased Superoxide Dismutase Activity in Aged Human Cerebrospinal Fluid and Rat Brain Determined by Electron Spin Resonance Spectrometry Using the Spin Trap Method

This study presents an e.s.r. assay for superoxide dismutase (SOD). Enzymic reactions were studied in which Cu,Zn-SOD, Mn-SOD and Fe-SOD each competed with the spin trap 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) for superoxide anion (O2-) at pH 7.8 O2- from dissolved KO2 (potassium superoxide) in dimethyl sulphoxide was added directly to the enzyme solutions containing DMPO. The results show that, in this competition reaction system, the kinetics of the reactions between the enzymes and O2- follow a function y = f[(SOD]0.5). The rate constant, kSOD = 6.4 x 10(9) M-1. S-1, determined for Cu,Zn-SOD is approximately an order of magnitude larger than those for Mn-SOD and Fe-SOD. A comparative study of reported SOD mimics, including Mn2+, MnO2-desferrioxamine mesylate (Desferal) and MnO2-Desferal-ascorbate, was done. The results show that solutions of these complexes are approximately three orders of magnitude less active than Cu,Zn-SOD and approximately two orders of magnitude less active than Mn-SOD or Fe-SOD. The results also suggest that the reactivity toward O2- in solutions of these complexes originates from the Mn2+ present and not from the MnO2-Desferal complexes.

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Inhibition of superoxide dismutase by nitroprusside and electron spin resonance observations on the formation of a superoxide-mediated nitroprusside nitroxyl free radical.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)90799-4 ◽

1984 ◽

Vol 259 (20) ◽

pp. 12678-12684

Author(s):

H P Misra

Keyword(s):

Superoxide Dismutase ◽

Electron Spin Resonance ◽

Free Radical ◽

Electron Spin ◽

Spin Resonance

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Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy

Journal of Toxicology ◽

10.1155/2011/973172 ◽

2011 ◽

Vol 2011 ◽

pp. 1-11

Author(s):

Shinobu Ito ◽

Tomohisa Mori ◽

Hideko Kanazawa ◽

Toshiko Sawaguchi

Keyword(s):

Free Radicals ◽

Electron Spin Resonance ◽

Electron Spin ◽

Spin Trap ◽

Detection Sensitivity ◽

Mouse Tissue ◽

Spin Adduct ◽

Simple Method ◽

Oxidation Stress ◽

Spin Resonance

Electron spin resonance (ESR) method is a simple method for detecting various free radicals simultaneously and directly. However, ESR spin trap method is unsuited to analyze weak ESR signals in organs because of water-induced dielectric loss (WIDL). To minimize WIDL occurring in biotissues and to improve detection sensitivity to free radicals in tissues, ESR cuvette was modified and used with 5,5-dimethtyl-1-pyrroline N-oxide (DMPO). The tissue samples were mouse brain, hart, lung, liver, kidney, pancreas, muscle, skin, and whole blood, where various ESR spin adduct signals including DMPO-ascorbyl radical (AsA∗), DMPO-superoxide anion radical (OOH), and DMPO-hydrogen radical (H) signal were detected. Postmortem changes in DMPO-AsA∗and DMPO-OOH were observed in various tissues of mouse. The signal peak of spin adduct was monitored until the 205th day postmortem. DMPO-AsA∗in liver (y=113.8–40.7 log (day),R1=-0.779,R2=0.6,P<.001) was found to linearly decrease with the logarithm of postmortem duration days. Therefore, DMPO-AsA∗signal may be suitable for detecting an oxidation stress tracer from tissue in comparison with other spin adduct signal on ESR spin trap method.

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