BIOL 108 |
| Reactive nitrogen species such as peroxynitrite produce 8-nitroguanine in both DNA and RNA. Its synthesis in nucleic acids has been associated with inflammation, chronic hepatitis C, gouty arthritis, and premalignant lesions. Presumably in vivo, peroxynitrite is produced in macrophages by the reaction of nitric oxide with superoxide, and the peroxynitrite so formed can then react with guanine to form 8-nitroguanine. Recently, nitro-tyrosine was produced in vitro by a Fenton type reaction. We have found that 8-nitroguanine can also be produced in vitro by a Fenton type reaction. Calf thymus DNA was dissolved in 5mM phosphate buffer, pH 7.01, and treated with hydrogen peroxide, sodium nitrite, and various iron (II) and iron (III) salts. The solutions were incubated with shaking at 37°C and aliquots of hydrogen peroxide and sodium nitrite added. The solutions were processed to isolate 8-nitroguanine, which spontaneously depurinates, and analyzed by HPLC using a C18 column and a photo-diode array detector. A compound whose retention time and spectra matched that of the 8-nitroguanine standard was found. The iron salts were not equally adept at producing 8-nitroguanine; this could be due to solubility or some unknown effect caused by the salts' anion. It is possible that production of some 8-nitroguanine in vivo maybe due to Fenton like reactions. |
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Chemistry and Metabolism
4:30 PM-6:30 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Biological Chemistry |