The effect of membrane cholesterol on the sodium pump in red blood cells.
The effect of membrane cholesterol on the sodium pump in red blood cells.
复制标题
膜胆固醇对红细胞钠泵的影响。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
F. Giraud
中科院分区：
文献类型：
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作者：
M. Claret;R. Garay;F. Giraud
1. 将人红细胞 (R.B.C.) 与磷脂酰胆碱囊泡一起孵育，以部分去除其膜胆固醇。在这些细胞中测定Na泵的动力学参数（亲和力和最大通量）并与对照进行比较。 2. 在存在内部 K 的情况下，进行性胆固醇消耗逐渐导致 (i) 最大通量增加 (ii) 对内部 Na 的表观亲和力降低。 3. 在没有内部 K 的情况下，胆固醇消耗没有明显的影响，表明观察到的变化是由内部 K 介导的。胆固醇消耗通过增加这两种 K 效应来发挥作用：(i) 最大通量的激活，和 (ii) 内部 Na 亲和力的降低。 4. 胆固醇效应（对钾泵相互作用）是特定的；它的发生没有任何变化（i）内部Na和无机磷酸盐以及外部Na和K的亲和力，以及（ii）泵送位点的数量。 5.在生理条件下，胆固醇降低了阳离子易位率并增加了泵对内部Na的选择性。
1. Human red blood cells (R.B.C.) were incubated with phosphatidylcholine vesicles to obtain partial depletion of their membrane cholesterol. The kinetic parameters of the Na pump (affinities and maximal fluxes) were determined in these cells and compared with controls. 2. In the presence of internal K, progressive cholesterol depletion induces gradually (i) an increase of the maximal flux (ii) a reduction of the apparent affinity for internal Na. 3. In the absence of internal K, cholesterol depletion has no apparent effect, indicating that the observed changes were mediated by the internal K. Cholesterol depletion acts by increasing these two K effects: (i) activation of the maximal fluxes, and (ii) reduction of the internal Na affinity. 4. The cholesterol effect (on the K‐pump interaction) is specific; it occurs without any change (i) in the affinities for internal Na and inorganic phosphate and for external Na and K, and (ii) in the number of pumping sites. 5. Under physiological conditions, cholesterol reduces the cation translocation rate and increases the selectivity of the pump for internal Na.