56287-13-9Relevant articles and documents
Simultaneous quantitation of N2,3-ethenoguanine and 1,N2-ethenoguanine with an immunoaffinity/gas chromatography/high-resolution mass spectrometry assay
Morinello,Ham,Ranasinghe,Sangaiah,Swenberg
, p. 327 - 334 (2001)
We have previously described an immunoaffinity/gas chromatography/electron capture negative chemical ionization high-resolution mass spectrometry (IA/GC/ECNCI-HRMS) assay for quantitation of the promutagenic DNA adduct N2,3-ethenoguanine (N2,3-εGua) in vivo. Here we present an expanded assay that allows simultaneous quantitation of its structural isomer, 1,N2-ethenoguanine (1,N2-εGua), in the same DNA sample. 1,N2-εGua and N2,3-εGua were purified together from hydrolyzed DNA using two immobilized polyclonal antibodies. GC/ECNCI-HRMS was used to quantitate the 3,5-bis(pentafluorobenzyl) (PFB) derivative of each adduct against an isotopically labeled analogue. Selected ion monitoring was used to detect the [M - 181]- fragments of 3,5-(PFB)2-N2,3-εGua and 3,5-(PFB)2-[13C4,15N 2]-N2,3-εGua and the [M - 201]- fragments of 3,5-(PFB)2-1,N2-εGua and 3,5-(PFB)2-[13C3]-1,N2-εGua. The demonstrated limits of quantitation in hydrolyzed DNA were 7.6 fmol of N2,3-εGua and 15 fmol of 1,N2-εGua in ～250 μg of DNA, which corresponded to 5.0 N2,3-εGua and 8.7 1,N2-εGua adducts/108 unmodified Gua bases, respectively. 1,N2-εGua was found to be the predominant ethenoguanine adduct formed in reactions of lipid peroxidation products with DNA. The respective ratios of 1,N2-εGua to N2,3-εGua were 5:1 and 38:1 when calf thymus DNA was treated with ethyl linoleate or 4-hydroxynonenal, respectively, under peroxidizing conditions. Only N2,3-εGua was detected in DNA treated with the vinyl chloride (VC) metabolite 2-chloroethylene oxide and in hepatocyte DNA from rats exposed to 1100 ppm VC for 4 weeks (6 h/day for 5 days/week). These data suggest that 1,N2-εGua plays a minor role relative to N2,3-εGua in VC-induced carcinogenesis, but that 1,N2-εGua may be formed to a larger extent from endogenous oxidative processes.
Analysis of 1,N2-ethenoguanine and 5,6,7,9-tetrahydro-7-hydroxy-9- oxoimidazo[1,2-α]purine in DNA treated with 2-chlorooxirane by high performance liquid chromatography/electrospray mass spectrometry and comparison of amounts to other DNA adducts
Mueller, Michael,Belas, Frank J.,Blair, Ian A.,Peter Guengerich
, p. 242 - 247 (1997)
High performance liquid chromatography (HPLC)/electrospray mass spectrometry methods were developed for the analysis of 1,N2- etheno(ε)guanine (Gua) and 5,6,7,9-tetrahydro-7-hydroxy-9-oxoimidazo[1,2- α]purine (HO-ethanoGua) [the cyclized form of N2-(2-oxoethyl)Gua] and its deoxyribose derivative in DNA. Evidence was provided for the formation of the latter adduct in DNA treated with 2-chlorooxirane, the reactive product formed from the carcinogen vinyl chloride. Measured levels of HO-ethanoGua and HO-ethanodeoxyguanosine were similar, although the assay for the deoxyribosyl derivative has some technical advantages. 3,N4-ε-Deoxycytidine was also estimated in 2-chlorooxirane-treated DNA using HPLC with fluorescence detection. Levels of all known adducts formed from vinyl chloride have now been estimated in DNA treated with 2-chlorooxirane and vary in the order N7-(2-oxoethyl)Gua >> 1,N6-ε-adenine > HO-ethanoGua > N2,3- ε-Gua > 3,N4-ε-cytosine > 1,N2-ε-Gua. Although in vivo adduct levels may not parallel these due to differential stability and rates of repair, analyses of the adducts in DNA treated with 2-chlorooxirane provide a basis for consideration of the biological effects of these adducts.
Reactions of 9-substituted guanines with bromomalondialdehyde in aqueous solution predominantly yield glyoxal-derived adducts.
Ruohola, Anne-Mari,Koissi, Niangoran,Andersson, Sanna,Lepistoe, Ilona,Neuvonen, Kari,Mikkola, Satu,Loennberg, Harri
, p. 1943 - 1950 (2007/10/03)
Reactions of 9-ethylguanine, 2'-deoxyguanosine and guanosine with bromomalondialdehyde in aqueous buffers over a wide pH-range were studied. The main products were isolated and characterized by (1)H and (13)C NMR and mass spectroscopy. The final products formed under acidic and basic conditions were different, but they shared the common feature of being derived from glyoxal. Among the 1 : 1 adducts, 1,N(2)-(trans-1,2-dihydroxyethano)guanine adduct (6) predominated at pH 7. In addition to these, an N(2)-(4,5-dihydroxy-1,3-dioxolan-2-yl)methylene adduct (11a,b) and an N(2)-carboxymethyl-1,N(2)-(trans-1,2-dihydroxyethano)guanine adduct (12) were obtained at pH 10. The results of kinetic experiments suggest that bromomalondialdehyde is significantly decomposed to formic acid and glycolaldehyde under the conditions required to obtain guanine adducts. Glycolaldehyde is oxidized to glyoxal, which then modifies the guanine base more readily than bromomalondialdehyde. Besides the glyoxal-derived adducts, 1,N(2)-ethenoguanine (5a-c) and N(2),3-ethenoguanine adducts (4a-c) were formed as minor products, and a transient accumulation of two unstable intermediates, tentatively identified as 1,N(2)-(1,2,2,3-tetrahydroxypropano)(8) and 1,N(2)-(2-formyl-1,2,3-trihydroxypropano)(9) adducts, was observed.
4-Hydroxy-2-nonenal and ethyl linoleate form N2,3-ethenoguanine under peroxidizing conditions
Ham, Amy-Joan L.,Ranasinghe, Asoka,Koc, Hasan,Swenberg, James A.
, p. 1243 - 1250 (2007/10/03)
In these studies, we demonstrate that N2,3-ethenoguanine (N2,3-∈Gua) is formed from lipid peroxidation as well as other oxidative reactions. Ethyl linoleate (EtLA) or 4-hydroxy-2-nonenal (HNE) was reacted with dGuo in the presence of tert-butyl hydroperoxide (t-BuOOH) for 72 h at 50 °C. The resulting N2,3-∈Gua was characterized by liquid chromatography/electrospray mass spectroscopy and by gas chromatography/high-resolution mass spectral (GC/HRMS) analysis of its pentafluorobenzyl derivative following immunoaffinity chromatography purification. The amounts of N2,3-∈Gua formed were 825 ± 20 and 1720 ± 50 N2,3-∈Gua adducts/106 normal dGuo bases for EtLA and HNE, respectively, corresponding to 38- and 82-fold increases in the amount of N2,3-∈Gua compared to controls containing only t-BuOOH. Controls containing t-BuOOH but no lipid resulted in a > 1000-fold increase in the level of N2,3-∈Gua over dGuo that was not subjected to incubation. EtLA and HNE, in the presence of t-BuOOH, were reacted with calf thymus DNA at 37 °C for 89 h. The amounts of N2,3-∈Gua formed in intact ctDNA were 114 ± 32 and 52.9 ± 16.7 N2,3-∈Gua adducts/106 normal dGuo bases for EtLA and HNE, respectively. These compared to 2.02 ± 0.17 and 2.05 ± 0.47 N2,3-∈Gua adducts/106 normal dGuo bases in control DNA incubated with t-BuOOH, but no lipid [13C18]EtLA was reacted with dGuo to determine the extent of direct alkylation by lipid peroxidation byproducts. These reactions resulted in a 89-93% level of incorporation of the 13C label into N2,3-∈Gua when EtLA and dGuo were in equimolar concentrations, when EtLA was in 10-fold molar excess, and when deoxyribose (thymidine) was in 10-fold molar excess. Similar reactions with ctDNA resulted in an 86% level of incorporation of the 13C label. These data demonstrate that N2,3-∈Gua is formed from EtLA and HNE under peroxidizing conditions by direct alkylation. The data also suggest, however, that N2,3-∈Gua is also formed by an alternative mechanism that involves some other oxidative reaction which remains unclear.
