FREE RADICAL-MEDIATED LIPID-PEROXIDATION IN CELLS - OXIDIZABILITY IS A FUNCTION OF CELL LIPID BIS-ALLYLIC HYDROGEN CONTENT
FREE RADICAL-MEDIATED LIPID-PEROXIDATION IN CELLS - OXIDIZABILITY IS A FUNCTION OF CELL LIPID BIS-ALLYLIC HYDROGEN CONTENT
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DOI：
10.1021/bi00181a003
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发表时间：
1994-04-19
期刊：
影响因子：
2.9
通讯作者：
BURNS, CP
中科院分区：
文献类型：
--
作者：
WAGNER, BA;BUETTNER, GR;BURNS, CP
在均相溶液中，脂类的氧化性随其不饱和程度线性变化。体外细胞以及体内氧化性研究通常依赖于过氧化反应的化学指标，如硫代巴比妥酸反应物质。为了研究细胞中脂质的氧化性，我们测量了氧摄取，并使用电子顺磁共振自旋捕获与α-（1-氧代-4-吡啶基）-N-叔丁基硝酮（POBN），脂质衍生的自由基的真实的时间产生。我们已经使用我们的实验在体外细胞脂质修饰模型，以检查脂质过氧化的速率和程度与L1210小鼠白血病细胞的脂质不饱和度。使用促氧化剂铁、抗坏血酸盐和醚脂质化合物1-O-十八烷基-2-Omethyl-rac-glycero-3-磷酸胆碱刺激脂质过氧化。我们做了总细胞脂质分析，以确定富含8种不同不饱和度脂肪酸的L1210细胞中所含的脂质碳-碳双键的数量。我们发现，在细胞脂质，（i）脂质链的长度没有明显的影响，自由基形成的速度或程度;（ii），产生的脂质自由基的最大量增加与细胞脂质中的双烯丙基位置的总数;和，最重要的是，（iii）细胞脂质过氧化反应的速度与双烯丙基位置的数量呈指数增加。我们的定量结果第一次清楚地表明，完整细胞的细胞脂质中所含的双烯丙基位置的数量决定了它们的易感性，即，氧化性，自由基介导的过氧化事件。
Oxidizability of lipids in homogeneous solution varies linearly with the extent of their unsaturation. In vitro cellular, as well as in vivo, studies Of oxidizability have generally relied upon chemical indicators of peroxidation such as thiobarbituric acid-reactive substances. To examine the oxidizability of lipids in cells, we have measured oxygen uptake and, using electron paramagnetic resonance spin trapping with alpha-(1-oxo-4-pyridyl)-N-tert-butylnitrone (POBN), the real time generation of lipid-derived free radicals. We have used our experimental in vitro cellular lipid modification model to examine the rate and extent of lipid peroxidation versus the degree of lipid unsaturation in L1210 murine leukemia cells. Lipid peroxidation was stimulated using the prooxidants iron, ascorbate, and the ether lipid compound 1-O-octadecyl-2-Omethyl-rac-glycero-3-phosphocholine. We did a total cellular lipid analysis to determine the number of lipid carbon-carbon double bonds contained in L1210 cells enriched with eight fatty acids of different degrees of unsaturation. We found in cellular lipids that (i) lipid chain length had no apparent effect on the rate or extent of radical formation; (ii), the maximum amount of lipid radical generated increases with the total number of bis-allylic positions in the cellular lipids; and, most importantly, (iii) the rate of cellular lipid peroxidation increases exponentially with the number of bis-allylic positions. Our quantitative results clearly demonstrate, for the first time, that the number of bis-allylic positions contained in the cellular lipids of intact cells determines their susceptibility, i.e., oxidizability, to free radical-mediated peroxidative events.