Glutathione thiyl

The key to hexavalent chromium s mutagenicity and possible carcinogenicity is the abiHty of this oxidation state to penetrate the cell membrane. The Cr(VI) Species promotes DNA strand breaks and initiates DNA—DNA and DNA-protein cross-links both in cell cultures and in vivo (105,112,128—130). The mechanism of this genotoxic interaction may be the intercellular reduction of Cr(VI) in close proximity to the nuclear membrane. When in vitro reductions of hexavalent chromium are performed by glutathione, the formation of Cr(V) and glutathione thiyl radicals are observed, and these are beHeved to be responsible for the formation of the DNA cross-links (112). 

Carbon monoxide has been used to scavenge OH fonned from the ozonolysis of alkenes. The CO2 tints generated was detected by FTIR spectroscopy and the "OH yields for individual reactions were calculated.239 The significance of the OH-induced intramolecular transformation of glutathione thiyl radicals to a-aminoalkyl radicals has been discussed with respect to its biological implications.240 The kinetics and mechanism of the process indicated that it could be a significant pathway for the selfremoval of glutathione thiyl radicals in vivo. 

Grierson L, Hildenbrand K, Bothe E (1992) Intramolecular transformation reaction of the glutathione thiyl radical into a non-sulphur-centered radical a pulse radiolysis and EPR study. Int J Radiat Biol 62 265-277... 

Zhao R, Lind J,Merenyi G, EriksonTE(1997) Significance of the intramolecular transformation of glutathione thiyl radicals to a-aminoalkyl radicals. Thermochemical and biological implications. J Chem Soc Perkin Trans 2 569-574... 

Aiyar J, Borges K, Floyd RA, et al. 1989. Role of chromium(V), glutathione thiyl radical and hydroxyl radical intermediates in chromium(VI)-induced DNA damage. Toxicol Environ Chem 22 135-148. 

Made) E, Wardman P. (2007) The oxidizing power of the glutathione thiyl radical as measured by its electrode potential at physiological pH. Arch Biochem Biophys 462 94-102. 

Glutathione thiyl radicals (GS ) can be produced e.g. when radicals from oxidable drugs redox cycle (ScHREiBER et al. 1989), or in the repair of oxidative stress (O Brien 1988) and radiation damage (Quintiliani et al. 1977). 

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