@misc{oai:repo.qst.go.jp:00073332, author = {Anzai, Kazunori and Matsumoto, Ken-ichiro and Nakanishi, Ikuo and 安西 和紀 and 松本 謙一郎 and 中西 郁夫}, month = {Aug}, note = {ABSTRACT The nitroxide radicals such as 4,4-dimethyl-oxazolidine-N-Oxyl (DOXYL) and 2,2,5,5-tetramethyl pyrrolidine-N-oxyl (PROXYL), both having 5-membered ring, and 2,2,6,6-tetramethylpiperidine -N-oxyl (TEMPO), having 6-membered ring, are stable free radicals when no redox-active compounds co-exist. Therefore, they can be used as ESR spin probes for spin labeling experiments. When redox-active compounds co-exist, the nitroxide radicals react with them and the nitroxide radicals are oxidized or reduced to be ESR-silent compounds depending on the species of the reacting redox-active compounds. These reactions can be used to evaluate the redox status of biological system by measuring ESR spectra. Sometimes, the nitroxide radicals can be used for protecting biological system from oxidative damage by reactive oxygen species such as hydroxyl radical. In this presentation, we will show several biological applications of the stable nitroxide radicals by referring our experimental results. \nREFERENCES [1] K. Nakagawa, K. Anzai, Lipids 45 (2010) 1081 [2] K. Anzai et al, Biochim. Biophys. Acta 1021 (1990) 21 [3] K. Anzai et al, Arch. Biochem. Biophys. 415 (2003) 251 [4] K. Anzai et al, Magn. Reson. Imaging 21 (2003) 765 [5] Z. Zelev et al, Chem. Commun. (2009) 53 [6] K. Takeshita et al, Biochim. Biophys. Acta, 1573 (2002) 156 [7] Y. Miura et al, Biochim. Biophys. Acta, 1525 (2001) 167 [8] K. Matsumoto et al, Mag. Resn. Med. 61 (2009) 1033 [9] K. Anzai et al, Free Radic. Biol. Med. 40 (2006) 1170, International Conference 2018 Modern Trends in Natural Sciences and Advanced Technologies in Science Education}, title = {Biological Applications of Stable Nitroxide Radicals as Redox Sensitive Compounds}, year = {2018} }