Distribution of 5-doxylstearic acid in the membranes of mammalian cells.
Distribution of 5-doxylstearic acid in the membranes of mammalian cells.
复制标题
5-强硬脂酸在哺乳动物细胞膜中的分布。
DOI：
10.1016/0005-2736(88)90446-4
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Dodd,NJ
中科院分区：
文献类型：
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作者：
Nettleton,DO;Morse2nd,PD;Dobrucki,JW;Swartz,HM;Dodd,NJ
用含氮5-十二烷基硬脂酸ESR谱的浓度依赖自旋展宽方法研究了5-十二烷基硬脂酸在正常小鼠胸腺-骨髓(TB)和中国仓鼠卵巢(CHO)细胞膜上的分布。用5-羟基硬脂酸标记了TB细胞、CHO细胞、红细胞和分离的CHO细胞质膜，并测量了所得ESR谱中心线的峰峰宽度。测得的谱线宽度与样品中加入的5-羟基硬脂酸的量在0-0.18摩尔氮氧化物/摩尔脂范围内呈线性关系。在红细胞中，在较低浓度的5-羟基硬脂酸时，线宽关系近似于线性函数，最高可达每摩尔脂0.07摩尔氮氧化物。给定量的5-十二烷基硬脂酸对完整细胞中心线的增宽量远小于红细胞或质膜，这表明5-十二烷基硬脂酸在完整细胞中具有更大的脂池。假设5-羟基硬脂酸在不同膜中的迁移率相似，5-羟基硬脂酸采样的脂水池的大小大致等于完整细胞中的总脂质。如果给定浓度的5-十二烷基硬脂酸只采样TB或CHO细胞的质膜，我们预计会看到与局部5-DOX硬脂酸浓度高12-20倍的线宽，因为CHO和TB细胞的质膜只占细胞总脂质的5%-8%。因此，5-十二烷基硬脂酸必须分布在完整细胞的大部分或全部细胞膜中，而不是仅定位于质膜。
Concentration-dependent spin broadening of ESR spectra of the nitroxide 5-doxylstearic acid has been used to evaluate the distribution of 5-doxylstearic acid in the membranes of intact mouse thymus-bone marrow (TB) and Chinese hamster ovary (CHO) cells. TB cells, CHO cells, erythrocytes, and isolated plasma membranes from CHO cells were labelled with 5-doxylstearic acid and the peak to peak linewidths of the central line of the resulting ESR spectra were measured. The measured line widths were linearly dependent on the amount of 5-doxylstearic acid incorporated into the sample over the range of 0–0.18 mol nitroxide per mol lipid. In erythrocytes, the relationship between linewidths approximated a linear function at lower concentrations of 5-doxylstearic acid, up to 0.07 mol nitroxide per mol lipid. The amount of broadening of the central line for a given amount of 5-doxylstearic acid was far less for intact cells than for either erythrocytes or plasma membrane, indicating that the 5-doxylstearic acid samples a much larger lipid pool in the intact cells. With the broad assumption that the mobility of the 5-doxylstearic acid is similar in different membranes, the size of the lipid pool sampled by 5-doxylstearic acid is approximately equal to the total cellular lipid in intact cells. If a given concentration of 5-doxylstearic acid sampled only the plasma membrane of TB or CHO cells, we would expect to see a linewidth corresponding to a 12–20-fold greater local concentration of 5-doxylstearic acid than was observed, since the plasma membranes of CHO and TB cells represent only 5–8 percent of the total cellular lipid. Therefore, the 5-doxylstearic acid must distribute into most or all cellular membranes of intact cells and is not localized in the plasma membrane alone.