Interaction between phloretin and the red blood cell membrane.
Interaction between phloretin and the red blood cell membrane.
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DOI：
10.1085/jgp.67.4.381
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发表时间：
1976-04
影响因子：
3.8
通讯作者：
Solomon, A K
中科院分区：
文献类型：
--
作者：
Jennings, M L;Solomon, A K
根皮素与红细胞成分的结合在 pH6 时进行了表征，此时结合和抑制效力最大。与完整红细胞和纯化血红蛋白的结合是程度大致相等的非饱和过程，这强烈表明大部分红细胞结合可能归因于血红蛋白。这一结论得到了以下事实的支持：不含同红蛋白的红细胞血影只能结合同等数量红细胞的 10% 的根皮素。红细胞膜对根皮素的渗透性已通过直接测量根皮素摄取的时间过程来确定。在2%的血细胞比容下，根皮素摄取的半衰期为8.7s，对应的渗透系数为2 x 10(-4) cm/s。与鬼魂结合的浓度依赖性揭示了两个可饱和成分。根皮素以高亲和力 (K diss = 1.5 muM) 与每个细胞约 2.5 x 10(6) 个位点结合；它还以较低的亲和力 (Kdiss = 54 muM) 与第二组位点（每个细胞 5.5 x 10(7)）结合。在红细胞血影的超声总脂质提取物中，根皮素结合由单一的可饱和成分组成。其亲和力和位点总数与鬼中的低亲和力结合过程没有显着差异。红细胞脂质提取物未表现出根皮素的高亲和力结合。因此，高亲和力根皮素结合位点与膜蛋白相关，低亲和力位点由根皮素与脂质结合产生。识别这两种类型的结合位点可以将根皮素对蛋白质介导的转运过程的影响与对膜脂质区域的影响区分开来。
Phloretin binding to red blood cell components has been characterized at pH6, where binding and inhibitory potency are maximal. Binding to intact red cells and to purified hemoglobin are nonsaturated processes approximately equal in magnitude, which strongly suggests that most of the red cell binding may be ascribed to hemoglobin. This conclusion is supported by the fact that homoglobin-free red cell ghosts can bind only 10% as much phloretin as an equivalent number of red cells. The permeability of the red cell membrane to phloretin has been determined by a direct measurement at the time-course of the phloretin uptake. At a 2% hematocrit, the half time for phloretin uptake is 8.7s, corresponding to a permeability coefficient of 2 x 10(-4) cm/s. The concentration dependence of the binding to ghosts reveals two saturable components. Phloretin binds with high affinity (K diss = 1.5 muM) to about 2.5 x 10(6) sites per cell; it also binds with lower affinity (Kdiss = 54 muM) to a second (5.5 x 10(7) per cell) set of sites. In sonicated total lipid extracts of red cell ghosts, phloretin binding consists of a single, saturable component. Its affinity and total number of sites are not significantly different from those of the low affinity binding process in ghosts. No high affinity binding of phloretin is exhibited by the red cell lipid extracts. Therefore, the high affinity phloretin binding sites are related to membrane proteins, and the low affinity sites result from phloretin binding to lipid. The identification of these two types of binding sites allows phloretin effects on protein-mediated transport processes to be distinguished from effects on the lipid region of the membrane.