Spin-trapping studies on the reactions of Cr(III) with hydrogen peroxide in the presence of biological reductants: is Cr(III) non-toxic?
Cr(III), which is thought to be relatively non-toxic, was reduced to Cr(II) ion by biological reductants such as L-cysteine and NADH and Cr(II) thus formed could easily react with hydrogen peroxide (H2O2) to yield very reactive active oxygen species, hydroxyl radical (.OH). The formation of hydroxyl radical was detected by water-soluble spin-traps, alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO). This result indicates that non-toxic Cr(III) compounds have the possibility of causing dangerous effects to living organism in the presence of biological reductants.
Ozawa
T
T
Division of Chemical Pharmacology, National Institute of Radiological Sciences, Chiba-shi, Japan.
Hanaki
A
A
D002857:Chromium / Q000378:metabolism*; D003497:Cyclic N-Oxides; D003545:Cysteine / Q000378:metabolism; D003553:Cystine / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000378:metabolism*; D006878:Hydroxides / Q000032:analysis / Q000378:metabolism; D017665:Hydroxyl Radical; D009243:NAD / Q000378:metabolism; D009589:Nitrogen Oxides; D010084:Oxidation-Reduction; D011725:Pyridines; D013113:Spin Labels
D003497:Cyclic N-Oxides; D006878:Hydroxides; D009589:Nitrogen Oxides; D011725:Pyridines; D013113:Spin Labels; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; D002857:Chromium; D009243:NAD; D017665:Hydroxyl Radical; D003553:Cystine; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D006861:Hydrogen Peroxide; D003545:Cysteine