期刊
CHEMICAL RESEARCH IN TOXICOLOGY
卷 18, 期 3, 页码 599-610出版社
AMER CHEMICAL SOC
DOI: 10.1021/tx049693d
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资金
- NCI NIH HHS [R01-CA91016] Funding Source: Medline
- NHLBI NIH HHS [P50-HL70128] Funding Source: Medline
Analysis of products from the reaction between 5(S)-hydroperoxy-6,8,11,14-(E,Z,Z,Z)eicosatetraenoic acid and 2'-deoxyguanosine in the presence of Fe-II, Fe-III, or vitamin C by liquid chromatography/atmospheric pressure chemical ionization/mass spectrometry revealed the presence of four DNA adducts. Surprisingly, adducts I and II had mass spectral characteristics identical to those for 1,N-2-etheno-2'-deoxyguanosine and heptanone-1,N-2-etheno-2'-deoxyguanosine. These adducts have previously been shown to arise from the homolytic decomposition of 13(S)-hydroperoxy-9,11-(Z,E)-octadecadienoic acid. It appears that under the reaction conditions, 5( 3)-hydroperoxy-6,8,11,14-(E,Z,Z,Z)-eicosatetraenoic acid was subjected to a previously unknown peroxidation reaction to give a bis-hydroperoxide intermediate that underwent a Hock rearrangement to produce 3(Z)-nonenal from the omega-terminus. The 3(Z)nonenal was then converted to 4-hydroperoxy-2-nonenal, a precursor to the formation of 4-oxo-2-nonenal. 4-Oxo-2-nonenal forms heptanone-1,N-2-etheno-adducts with 2'-deoxyguanosine, whereas 4-hydroperoxy-2-nonenal forms 1,N-2-etheno-2'-deoxyguanosine. Two novel carboxylate adducts were also identified. The structure of the more abundant adduct (III) was characterized as its methyl ester derivative by NMR spectroscopy as 3-(2'-deoxy-beta-D-erythropentafuranosyl)-imidazo-7-(5 ''-carboxypenta-2 ''-one)-9-oxo[1,2-alpha]purine (5-carboxy-2-pentanone-1,N-2-etheno-2'-deoxyguanosine). This etheno adduct was formed by the reaction of 2'-deoxyguanosine with 5,8-dioxo-6(E)-octenoic acid. The bifunctional electrophile is proposed to arise from the a-terminus during the Hock rearrangement of bis-hydroperoxide derived from 5(S)-hydroperoxy-6,8,11,14-(E,Z,Z,Z)-eicosatetraenoic acid. 5-Carboxy-2-pentanone-1,N-2-etheno-2'-deoxyguanosine may serve as a biomarker of 5-lipoxygenase-mediated oxidative stress. The less abundant carboxylate adduct IV arose from a quite different pathway and was tentatively characterized as 6-carboxy-3-hydroxy-1-hexene-1,N-2-etheno-2'-deoxyguanosine.
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