Mechanism of DNA damage induced by bromate differs from general types of oxidative stress.
A representative reactive oxygen species (ROS), hydroxyl radical (*OH), is a highly reactive species and induces DNA backbone breakage. *OH also oxidizes every DNA base. The interaction of *OH with guanine leads to the generation of not only piperidine-resistant 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) but also various piperidine-labile products. On the other hand, potassium bromate (KBrO3) induces specific formation of 8-oxodG in the presence of SH compounds, such as glutathione (GSH) and cysteine (Cys). GSH/Cys reduces KBrO3 (BrO3-) to BrO2, which abstracts one electron from guanine. The one-electron oxidation of guanine may yield cation radicals followed by the reaction with a water molecule, leading to 8-oxodG formation. Therefore, mechanism of bromate-induced oxidative DNA damage is different from general types of oxidative stress such as *OH.
Kawanishi
Shosuke
S
Department of Environmental and Molecular Medicine, Mie University School of Medicine, 2-174, Edobashi, Tsu, Mie 514-8507, Japan. kawanisi@doc.medic.mie-u.ac.jp
Murata
Mariko
M
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D001959:Bromates / Q000633:toxicity*; D003545:Cysteine / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004579:Electron Transport; D005978:Glutathione / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D007680:Kidney Neoplasms / Q000139:chemically induced* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
D001959:Bromates; D017382:Reactive Oxygen Species; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; C427203:calf thymus DNA; D003849:Deoxyguanosine; D005978:Glutathione; D003545:Cysteine