Qian Steven Yue, Yue Gui-Hua, Tomer Kenneth B, Mason Ronald P
Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA. qian
Free Radic Biol Med. 2003 Apr 15;34(8):1017-28. doi: 10.1016/s0891-5849(03)00031-5.
Using the combined techniques of on-line high performance liquid chromatography/electron spin resonance (LC/ESR) and mass spectrometry (MS), we previously identified spin-trapped adducts of all expected carbon-centered lipid-derived radicals (()L(d)) formed in linoleic acid peroxidation. In the present study, spin trapped lipid-derived carbon-centered radicals formed from the reactions of two omega-6 polyunsaturated fatty acids (PUFAs: linoleic and arachidonic acids) with soybean lipoxygenase in the presence of alpha-[4-pyridyl 1-oxide]-N-tert-butyl nitrone (POBN) were identified using a combination of LC/ESR and LC/MS. All expected lipid-derived carbon-centered radicals in lipoxygenase-dependent peroxidations of linoleic acid and arachidonic acid were detected and identified by the combination of LC/ESR and LC/MS with confirmation by tandem mass spectrometry (MS/MS). The five classes of ()L(d) formed from both omega-6 PUFAs including lipid alkyl radicals (L()), epoxyallyic radicals (OL()), dihydroxyallyic radicals (()L(OH)(2)), and a variety of R() and ()RCOOH from beta-scission of lipid alkoxyl radicals, gave distinct retention times: POBN/()L(OH)(2) approximately 4-6 min, POBN/R() and POBN/()RCOOH approximately 8-22 min, POBN/L() and PBON/OL() approximately 25-36 min. The major beta-scission products in peroxidations of omega-6 PUFAs were the pentyl radicals. The ratio of beta-scission products, however, varied significantly depending on pH, [PUFA], as well as [O(2)].
我们先前运用在线高效液相色谱/电子自旋共振（LC/ESR）和质谱（MS）联用技术，鉴定出了亚油酸过氧化过程中形成的所有预期的以碳为中心的脂质衍生自由基（()L(d)）的自旋捕获加合物。在本研究中，使用LC/ESR和LC/MS联用技术，鉴定了在α-[4-吡啶基1-氧化物]-N-叔丁基硝酮（POBN）存在下，两种ω-6多不饱和脂肪酸（PUFAs：亚油酸和花生四烯酸）与大豆脂氧合酶反应形成的自旋捕获脂质衍生碳中心自由基。通过LC/ESR和LC/MS联用，并经串联质谱（MS/MS）确认，检测并鉴定了亚油酸和花生四烯酸脂氧合酶依赖性过氧化过程中所有预期的以碳为中心的脂质衍生自由基。由两种ω-6多不饱和脂肪酸形成的五类()L(d)，包括脂质烷基自由基（L()）、环氧烯丙基自由基（OL()）、二羟基烯丙基自由基（()L(OH)(2)），以及脂质烷氧基自由基β-断裂产生的各种R()和()RCOOH，具有不同的保留时间：POBN/()L(OH)(2)约为4 - 6分钟，POBN/R()和POBN/()RCOOH约为8 - 22分钟，POBN/L()和PBON/OL()约为25 - 36分钟。ω-6多不饱和脂肪酸过氧化过程中的主要β-断裂产物是戊基自由基。然而，β-断裂产物的比例会因pH、[PUFA]以及[O(2)]的不同而有显著变化。
