Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Kamibayashi, Masato*; Yamashita, Masayuki*; Anzai, Kazunori*; Katsumura, Yosuke*
Analytical Chemistry, 83(24), p.9600 - 9604, 2011/10
Times Cited Count:39 Percentile:78.17(Chemistry, Analytical)Chemical reactions of a novel gauche-type spin trap, G-CYPMPO (-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphinan-2-yl)-5-methy-1-pyrroline 1-oxide, torsion angle: O1-P1-C6-N1 of 52.8), with reactive oxygen species were examined by pulse radiolysis technique with 35 MeV electron beam and electron spin resonance spectroscopy after Co -ray irradiation. The spin trapping reaction rate constants of G-CYPMPO toward hydroxyl radical and hydrated electron were estimated to be (4.20.1)10 and (11.80.2)10 Ms, respectively. Half-lives of spin adducts, hydroxyl radical and perhydroxyl radical adducted G-CYPMPO were estimated to be 35 and 90 min, respectively. A comparison of the results with earlier reports using different radical sources suggests that the purity of the solution and/or the radical generation technique may influence the stability of spin adducts.
Midorikawa, Masamichi*; Yamashita, Shinichi; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Maeyama, Takuya*; Funtowiez, D.*; Kamibayashi, Masato*; Anzai, Kazunori*
no journal, ,
no abstracts in English
Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke
no journal, ,
Detection and quantification of the oxidative radicals such as hydroxyl radical or superoxide anion radical are very important to clarify the biological oxidative damages. These oxidative radicals, produced by water decomposition with -ray irradiation, were detected as spin adducts of CYPMPO and themselves. In this work, reactivity CYPMPO and behavior of spin adducts were investigated.
Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke
no journal, ,
The oxygen radicals play a crucial role in biological oxidative damage. It is important to clarify behavior of hydroxyl and superoxide radicals, detection and quantification of these radicals are required. In present work, the reactivities of CYPMPO toward a hydrated electron and a hydroxyl radical utilizing a pulse radiolysis system are investigated, and compared with DMPO (5,5-Dimethyl-1-pyrroline N-oxide) results. The oxygen radicals produced by -ray irradiation are also discussed.
Midorikawa, Masamichi*; Oka, Toshitaka; Yamashita, Shinichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke
no journal, ,
5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1pyrroline N-oxide (CYPMPO) is a recently developed spin-trapping agent, which is expected to distinguish O from OH. We have determined its reactivity with water decomposed radicals, especially with OH and with e by pulse radiolysis, and compared results with commonly-used spin trapping agent, 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Furthermore, the reactions with oxidative radicals such as COO, NO and Br have also been investigated.
Delamea, N.*; Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Midorikawa, Masamichi*; Katsumura, Yosuke; Kamibayashi, Masato*; Anzai, Kazunori*
no journal, ,
In order to measure the transient radicals quantitatively, the spin trapping technique with a newly developed CYPMPO in 2006 has been applied to detect the water decomposition and secondary radicals using by ESR (Electron Spin Resonance) spectroscopy. We have succeeded to identify five radicals assigned to the spin adducts of OH, O, HO, COO and H.
Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Midorikawa, Masamichi*; Delamea, N.*; Katsumura, Yosuke; Kamibayashi, Masato*; Anzai, Kazunori*
no journal, ,
A novel spin-trap CYPMPO (5-(2,2-dimethyl-1,3-propoxy cyclophos-phoryl)-5-methyl-1-pyrroline N-oxide) was applied to detect the water decomposed radicals using by ESR (Electron Spin Resonance) spectroscopy, and their lifetimes were estimated.