Peroxynitrite is a strong oxidant formed by reaction of nitric oxide with superoxide in inflamed tissues. We have demonstrated that 8-nitroguanine is formed dose-dependently in calf thymus DNA incubated with low concentrations of peroxynitrite in vitro. 8-Nitroguanine in acid-hydrolyzed DNA was chemically reduced into 8-aminoguanine, which was analyzed using high performance liquid chromatography with electrochemical detection. Only peroxynitrite, but not nitrite, tetranitromethane nor NO-releasing compounds, formed 8-nitroguanine. Antioxidants and desferrioxamine inhibited the reaction. 8-Nitroguanine was depurinated from DNA incubated at pH 7.4, 37°C (01281-6/asset/equation/feb20014579395012816-math-si1.gif?v=1&s=542d06ac27ff9f1fa1d8b97274c63a06fd9afdb1)
). Peroxynitrite did not increase 8-oxoguanine levels in DNA.
