Ascorbate free radical as a marker of oxidative stress: an EPR study.
The ascorbate free radical (A.-) is a resonance-stabilized tricarbonyl species that is readily formed from the one-electron oxidation of ascorbate, AH-. Because of the low reduction potential of the A.-/AH- couple, Eo' = +282 mV, nearly every oxidizing radical that can arise in a biological system will bring about the one-electron oxidation of AH-, forming A.-. Thus, the steady-state concentration of A.- can be used as a measure of oxidative stress in chemical, biochemical, and biological systems. In this article, we discuss the energetics of ascorbate free radical reactions and demonstrate that the A.- electron paramagnetic resonance (EPR) signal intensity can serve as a marker for the degree of oxidative stress occurring in a system.
ESR Facility/EMRB 68, College of Medicine, University of Iowa, Iowa City 52242.
G R
GR
Buettner
B A
BA
Jurkiewicz
D000578:Amidines / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry*; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D066298:In Vitro Techniques; D010084:Oxidation-Reduction; D012256:Riboflavin / Q000737:chemistry; D013113:Spin Labels; D013816:Thermodynamics; D014969:Xanthine Oxidase / Q000737:chemistry
D000578:Amidines; D003497:Cyclic N-Oxides; D005609:Free Radicals; D013113:Spin Labels; C017245:5,5-dimethyl-1-pyrroline-1-oxide; C046728:2,2'-azobis(2-amidinopropane); D014969:Xanthine Oxidase; D001205:Ascorbic Acid; D012256:Riboflavin