期刊名称：Journal of Clinical Biochemistry and Nutrition
印刷版ISSN：0912-0009
电子版ISSN：1880-5086
出版年度：2005
卷号：36
期号：2
页码：51-57
DOI：10.3164/jcbn.36.51
出版社：The Society for Free Radical Research Japan
摘要：Tetrahydrobiopterin (BH4) prevented an increase in the formation of 8-hydroxydeoxyguanosine (8-OHdG) in calf thymus DNA by the peroxynitrite (ONOO-) or Fe2+ + hydrogen peroxide (H2O2) system. But, the addition of BH4 to the Cu2+ + ascorbic acid (AsA) system caused a very large increase in base damage. Without the addition of AsA (in the presence of Cu2+ alone), BH4 could also induce 8-OHdG formation. Experiments utilizing the Cu+ chelator bathocuproine, catalase and superoxide dismutase revealed that Cu+ and H2O2 intermediates relate to Cu2+ + BH4-induced 8-OHdG formation. Electron spin resonance experiments also showed that the hydroxyl radical is not a major intermediate. These results suggest that although BH4 is known to prevent oxidative damage in proteins and lipids, it has the potential to cause oxidative DNA damage depending on the existence of copper ions.
