Retinoic acid-dependent stimulation of 2,2'-azobis(2-amidinopropane)-initiated autoxidation of linoleic acid in sodium dodecyl sulfate micelles: a novel prooxidant effect of retinoic acid.
Retinoic acid-dependent stimulation of 2,2'-azobis(2-amidinopropane)-initiated autoxidation of linoleic acid in sodium dodecyl sulfate micelles: a novel prooxidant effect of retinoic acid.
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DOI：
10.1021/tx970044u
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发表时间：
1998
影响因子：
4.1
通讯作者：
M. A. Freyaldenhoven;P. Lehman;T. Franz;R. Lloyd;V. Samokyszyn
中科院分区：
文献类型：
--
作者：
M. A. Freyaldenhoven;P. Lehman;T. Franz;R. Lloyd;V. Samokyszyn
(E)-维甲酸（RA）可刺激十二烷基硫酸钠（SDS）胶束中2,2'-偶氮（2-氨基氨基丙烷）（AAPH）引发的亚油酸自氧化（18:2）的速率。ra依赖的18:2自氧化刺激的特征是双氧摄取率与类视黄醛浓度成线性关系。相反，RA的主要氧化产物5,6-环氧-RA在所有测试浓度下都没有影响双氧消耗速率。当苯乙烯作为分子探针包含在胶束体系中时，RA也被证明可以刺激苯乙烯的过氧基依赖氧化成相应的氧环烷。此外，通过对13-羟基-(9Z, 11E)-十八碳二烯酸（13-HODE）和9-羟基-(10E,12Z)-十八碳二烯酸（9-HODE）产量的相对定量，获得了明确的ra依赖性刺激18:2自氧化的证据。此外，利用α -（4-吡啶基- 1-氧化物）- n-叔丁基硝基酮（4-POBN）作为自旋阱，通过EPR光谱证实了RA存在下碳中心自由基形成的增强。对RA氧化产物的分析和定量表明，RA被氧化为一个初级产物5,6-环氧-RA，通过合成标准品共色谱（反相高效液相色谱系统）、电子吸收光谱和相应甲酯的正化学电离质谱鉴定。其他少量氧化产物也被检测到，但未被表征。相反，缺乏18:2的反应混合物没有表现出明显的类维生素a氧化。提出了机制来解释RA在该系统中的促氧化作用。
(E)-Retinoic acid (RA) was shown to stimulate the rate of 2,2'-azobis(2-amidinopropane) (AAPH)-initiated autoxidation of linoleic acid (18:2) in sodium dodecyl sulfate (SDS) micelles. RA-dependent stimulation of 18:2 autoxidation was characterized by enhanced rates of dioxygen uptake which were linear with retinoid concentration. In contrast, 5,6-epoxy-RA, a major oxidation product of RA, failed to affect the rate of dioxygen consumption at all concentrations tested. RA was also shown to stimulate peroxyl radical-dependent oxidation of styrene to the corresponding oxirane when styrene was included in the micellar system as a molecular probe. Furthermore, unequivocal evidence of RA-dependent stimulation of 18:2 autoxidation was obtained by relative quantitation of 13-hydroxy-(9Z, 11E)-octadecadienoic acid (13-HODE) plus 9-hydroxy-(10E,12Z)-octadecadienoic acid (9-HODE) production. In addition, enhanced carbon-centered radical formation was demonstrated in the presence of RA by EPR spectroscopy using alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (4-POBN) as a spin trap. Analysis and quantitation of RA oxidation products indicated that RA was oxidized to one primary product, 5,6-epoxy-RA, which was identified on the basis of cochromatography with synthetic standard (in a reverse-phase HPLC system), electronic absorption spectroscopy, and positive chemical ionization mass spectrometry of the corresponding methyl ester. Other minor oxidation products were also detected but not characterized. In contrast, reaction mixtures devoid of 18:2 failed to demonstrate significant retinoid oxidation. Mechanisms are proposed to account for the prooxidant effects of RA in this system.