Table 1.

Chemical equations relevant to reactive oxygen and reactive nitrogen species generation.

Reactive oxygen species generation

O2 + e− → O2−• (superoxide anion)

O2 −•+ H2O → HO2• (hydroperoxyl radical)

HO2• + e− + H → H2O2 (hydrogen peroxide)

H2O2 + e− → OH− + •OH (hydroxyl radical)

Reactive nitrogen species generation

L-arginine + O2 → •NO (nitric oxide) + L-citrulline

O2− • + •NO → ONOO− (peroxynitrite)

ONOO− + CO2 → ONOOCO2− (nitrosoperoxy carbonate)

ONOOCO2− → •NO2 (nitrogen dioxide) + CO3− • (carbonate anion radical)

Fenton reaction (catalyzed by transition metals)

H2O2 + Fe2+ → OH− + •OH + Fe3+

Haber-Weiss Reaction (catalyzed by transition metals)

H2O2 + O2− • → O2+ •OH + OH−

^*Reprinted with permission from Klaunig JE, Kamendulis LM. The role of oxidative stress in carcinogenesis. Annu Rev Pharmacol Toxicol. 44:239–267,2004. [79]