Details

Autor(en) / Beteiligte

• Shi, Xianglin
• Dalal, N.S.

Titel

Evidence for a fenton-type mechanism for the generation of .OH radicals in the reduction of Cr(VI) in cellular media

Ist Teil von

• Archives of biochemistry and biophysics, 1990-08, Vol.281 (1), p.90-95

Ort / Verlag

San Diego, CA: Elsevier Inc

Erscheinungsjahr

1990

Quelle

ScienceDirect

Beschreibungen/Notizen

• Electron spin resonance (ESR) spectroscopy has been employed to examine the role of tetraperoxochromate(V) ions (CrO 8 3−) and other Cr(V) species in the generation of hydroxyl (.OH) radicals in the reaction of Cr(VI) with H 2O 2 in biological media. In contrast to earlier suggestions, the present ESR studies using crystalline K 3CrO 8 as a source of CrO 8 3−show that decomposition of CrO 8 3− in water or in H 2O 2 does not generate significant amounts of .OH radicals. Addition of NADH to a solution containing CrO 8 3− yields a Cr(V)-NADH complex, which readily reacts with H 2O 2 to generate .OH radicals. Similar results obtained from several other biological reductants, including vitamin B 2, indicate that a vacant coordination site on a Cr(V) complex facilitates its reaction with H 2O 2 to generate .OH radicals. We thus suggest that in biological media, reaction [3]instead of [1] or [2] is the major pathway for the .OH radical generation: ▪ ▪ ▪.