過氧化亞硝酸根負離子和其他高反應性物種與DNA作用產生之加成產物的研究

• Main Author: 王光賢
• Other Authors: 陳皓君
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/61647109006740079590

碩士 === 國立中正大學 === 化學研究所 === 89 === Actived phagocytic cells generate reactive nitrogen species, include nitryl chloride and peroxynitrite, for defense against invading pathogens. It has been proposed that these reactive nitrogen species may cause DNA damage and thus contribute to the multistage carcinogenesis process associated with chronic infections and inflammation. Previous studies showed that peroxynitrite reacted with guanine, 2’-deoxyguanosine, or DNA forming 8-nitroguanine. We herein report formation of 8-nitroxanthine as the major nitration product in reaction of 2’-deoxyguanosine or calf thymus DNA with nitryl chloride produced by mixing nitrite with hypochlorous acid , and 8-nitroguanine was a minor product in these reaction. 8-nitroxanthine was characterized by its laser desorption ionization mass spectra and by deamination of 8-nitroguanine. Levels of 8-nitroguanine and 8-nitroxanthine in these reactions were quantified by reversed—phase HPLC with photodiode array detection. Once formed, 8-nitroxanthine was spontaneously removed from DNA with a half-life of 2 h at 37℃ and pH 7.4. Therefore, 8-nitroxanthine might be an important DNA lesion derived from reactive nitrogen species in vivo.