콘텐츠로 건너뛰기
Merck
  • Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base.

Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base.

Free radical biology & medicine (2011-12-27)
Gyorgy Hajas, Attila Bacsi, Leopoldo Aguilerra-Aguirre, Peter German, Zsolt Radak, Sanjiv Sur, Tapas K Hazra, Istvan Boldogh
초록

8-Oxo-7,8-dihydroguanine is one the most abundant base lesions in pro- and eukaryotic DNA. In mammalian cells, it is excised by the 8-oxoguanine DNA glycosylase (OGG1) during DNA base-excision repair, and the generated free 8-oxoG base is one of the DNA-derived biomarkers of oxidative stress in biological samples. The modification of 8-oxoG in the context of nucleoside and DNA has been the subject of many studies; however, the oxidative transformation of the free 8-oxoG base has not been described. By using biochemical and cell biological assays, we show that in the presence of molecular oxygen, the free 8-oxoG base transforms to a highly reactive hydroperoxide (8-oxoG*). Specifically, 8-oxoG* oxidizes Amplex red to resorufin, H(2)DCF to DCF, Fe(2+) to Fe(3+), and GSH to GSSG. This property of 8-oxoG* was diminished by treatment with catalase and glutathione peroxidase, but not superoxide dismutase. 8-OxoG* formation was prevented by reducing agents or nitrogen atmosphere. Its addition to CM-H(2)DCF-DA-loaded cells rapidly increased intracellular DCF fluorescence. There were no such properties observed for 8-oxodeoxyguanosine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 2'-deoxyguanosine, guanine, adenine, guanosine, and 8-hydroxyadenine. These data imply that a free 8-oxoG base is more susceptible to oxidation than is its nucleoside form and, consequently, it stands as unique among intact and oxidatively modified purines.

MATERIALS
제품 번호
브랜드
제품 설명

Sigma-Aldrich
2′,7′-Dichlorofluorescein, ACS reagent
Sigma-Aldrich
2′,7′-Dichlorofluorescein, BioReagent, suitable for fluorescence, ≥90% (T)
Sigma-Aldrich
2′,7′-Dichlorofluorescein, suitable for use as an indicator in chloride titration, ~90% (TLC), powder