کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1911556 | 1046822 | 2007 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Dual activity of nitroxides as pro- and antioxidants: Catalysis of copper-mediated DNA breakage and H2O2 dismutation
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کلمات کلیدی
TPO2,2,6,6-tetramethylpiperidine-N-oxylo-PhenanthrolineSSBDSB3-cp - 3 سHydrogen peroxide - آب اکسیژنهAntioxidant - آنتی اکسیدانphosphate buffer - بافر فسفاتFree radicals - رادیکال آزادRno - رنوsingle-strand breaks - شکاف تک رشته ایdouble-strand breaks - شکست دو ردیفDNA breakage - شکستگی DNAPro-oxidant - طرفدار اکسیدانCopper - مسNitroxide - نیتروکسیدHydroxylamine - هیدروکسیلامین
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Nitroxide antioxidants can be reduced to hydroxylamines or oxidized to oxoammonium cations. Consequently, nitroxides can modify oxidative damage acting as reducing and/or as oxidizing agents, and in many cases the nitroxides are continuously recycled. They provide protection against oxidative stress via various mechanisms including SOD-mimic activity and detoxification of carbon-, oxygen-, and nitrogen-centered radicals, as well as oxidation of reduced transition metals. In contrast to the common concept, according to which the nitroxides' protective effect takes place via inhibition of the Fenton reaction, there are observations suggesting the opposite. In the present investigation, DNA breakage catalyzed by copper served as an experimental model for studying the anti- and pro-oxidative activity of nitroxides. Nitroxides provided protection in the presence of GSH, which is known to facilitate metal-catalyzed DNA damage. In the absence of a reductant, nitroxides enhanced DNA breakage under aerobic conditions with or without added H2O2 and facilitated H2O2 depletion. The rates of nitroxide-catalyzed DNA breakage and H2O2 depletion increased as the concentrations of copper, H2O2, and nitroxide increased. Although the catalytic activity of nitroxides is low, it is sufficient to induce DNA breakage. The efficacy of DNA breakage by the tested piperidine nitroxides correlated with the nitroxide-induced depletion of H2O2 with the exception of the pyrrolidine nitroxide 3-carbamoylproxyl. The results suggest that the nitroxide and the copper are continuously recycled while catalyzing DNA breakage and depletion of H2O2, which serves both as a source of reducing equivalents and as the electron sink.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 42, Issue 9, 1 May 2007, Pages 1317-1325
Journal: Free Radical Biology and Medicine - Volume 42, Issue 9, 1 May 2007, Pages 1317-1325
نویسندگان
Yaacov Aronovitch, Dina Godinger, Avner Israeli, Murali C. Krishna, Amram Samuni, Sara Goldstein,