Lipid translocation across the human erythrocyte membrane. Regulatory factors.
Lipid translocation across the human erythrocyte membrane. Regulatory factors.
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发表时间：
1982-06
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通讯作者：
N. Mohandas;J. Wyatt;S. Mel;M. Rossi;S. Shohet
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作者：
N. Mohandas;J. Wyatt;S. Mel;M. Rossi;S. Shohet
建立了一种基于生理盐水和白蛋白溶液对溶血磷脂酰胆碱（LPC）的差异提取的简单方法，用于研究脂质跨完整人红细胞膜转运的影响因素。通过该测定，发现在37 ° C下LPC跨双层易位的速率为1.87%h（0.0187 h-1）。正常细胞和ATP完全耗尽的细胞的易位率相同，这意味着细胞的代谢状态没有影响。相反，易位率受温度的强烈影响。在21摄氏度以上，温度每升高51摄氏度，速率就增加一倍，这表明通过脂质相扩散的重要作用。通过将细胞加热至5摄氏度使单一主要骨骼蛋白血影蛋白变性并没有改变易位率。然而，通过用二酰胺处理膜蛋白复合物的氧化交联显著增加了37 ℃下的易位率。胆固醇富集的细胞减少表观易位率，但不转运的LPC的总量。两者合计，这些数据表明，脂质易位穿过完整的人红细胞膜是不依赖于能量的，它是由膜的脂质和蛋白质部分的组织状态的影响。
A simple method based on the differential extraction of lysophosphatidylcholine (LPC) by saline and albumin solutions has been developed to study the factors that influence lipid translocation across intact human erythrocyte membrane. With this assay, the rate of LPC translocation across the bilayer at 37 degrees C was found to be 1.87% h (0.0187 h-1). Identical translocation rates were derived for normal cells and cells in which the ATP was totally depleted, implying that the metabolic state of the cell had no influence. In contrast, the translocation rate was strongly influenced by temperature. Above 21 degrees C, the rate doubled for every 51 degrees C increase in temperature, suggesting an important role for diffusion through the lipid phase. Denaturation of a single major skeletal protein, spectrin, by heating cells to 5 degrees C did not alter the translocation rate. However, oxidative cross-linking of a complex of membrane proteins by treatment with diamide significantly increased the rate of translocation at 37 degrees C. Cholesterol enrichment of the cells decreased the apparent rate of translocation but not the total quantity of LPC translocated. Taken together, these data suggest that lipid translocation across the intact human erythrocyte membrane is not energy dependent, and that it is influenced by the organizational state of both the lipid and protein moieties of the membrane.