5,5-Dimethyl-l-pyrroline-N-oxide DMPO

Tetrachloro-l,4-benzoquinone, a carcinogenic metabolite of the wood-preservative pentachloro-phenol, when incubated with the spin-trapping agent 5,5-dimethyl-l-pyrroline N-oxide (DMPO) and H2O2 produced the DMPO/HO adduct (Zhu etal. 2002). The formation of DMPO/HO was markedly inhibited by the HO scavenging agents dimethyl sulphoxide (DMSO), ethanol, formate, and azide, with the concomitant formation of the characteristic DMPO spin trapping adducts with CHj, CH(CH3)0H, COO", and Nj, respectively. 

As a means of identifying the potent oxidant another approach was made. By the use of certain organic compounds one can infer the presence of a free radical by converting a highly unstable one such as OH to a much more stable compound which can accumulate in solution, rendering its detection by electron spin resonance possible. To measure the presence of OH the compound DMPO (5,5-dimethyl l-pyrroline-N-oxide) has been used The characteristic adduct of OH with... 

The EPR spin-trapping techniques were used to obtain evidence for the formation of a radical intermediate in the biomimetic Fe(n)-induced degradation of arteflene 194 in the presence of sodium 3,5-dibromo-4-nitrosobenzene-sulfonate (DBNBS) and 5,5-dimethyl-l-pyrroline /V-oxide (DMPO) <2000JOC1578>. 

Spin-traps DMPO (5,5-dimethyl-l- pyrroline-N-oxide), MNP (2-methyl-2-nitroso-propane, dimer), dG (2 -deoxyguanosine monophosphate), 8-HOdG standard (8-hydroxy-2 -deoxyguanosine) and deferoxamine mesylate were purchased from Sigma phosphate buffer (pH 7.4), hydrogen peroxide (H2O2) (30%), were purchased from Merck. All other chemicals used were of analytical quality. 

Note Values were taken from A. B. Ross, NDRL/NIST Solution Kinetics Database, v. 2.0, Standard Reference Data, NIST, Gaithersburg, MD 20899, USA (http //allen.rad.nd.edu), also found in Ref. 32. DMPO stands for 5,5-dimethyl-l-pyrroline N-oxide. 

ATP, adenosine 5 -triphosphate BH4, 5,6,7,8-tetrahydrobiopterin BMPO, 5- er -butoxycarbonyl-5-pyrroline A-oxide DBNBS, 3,5-dibromo-4-nitrosoben-zene sulfonate DEPMPO, 5-diethoxyphosphoryl-5-methyl-l-pyrroline A-ox-ide DMPO, 5,5-dimethyl- 1-pyrroline A-oxide EMPO, 5-ethoxycarbonyl-5-methyl-l-pyrroline A-oxide GSH, glutathione (y-L-glutamyl-L-cysteinyl-glycine) HRP, horseradish peroxidase MNP, 2-methyl-2-nitrosopropane MPO, myeloperoxidase NAD(P)H, fl-nicotinamine adenine dinucleotide (3 -phosphate), reduced from NMDA, A-methyl-D-aspartic acid PBN, N-tert-butyl-a-phenylnitrone PMN, polymorphonuclear lymphocyte POBN, a-(4-pyridyl-l-oxide)-A-fer -butylnitrone SOD, superoxide dismutase TEMP,... 

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