Matsumoto M, Yamaguchi T, Terada S, Kimoto E
Department of Chemistry, Faculty of Science, Fukuoka University, Japan.
Biochim Biophys Acta. 1996 Apr 26;1280(2):243-50. doi: 10.1016/0005-2736(95)00302-9.
Effects of anion transport inhibitors such as 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate on hemolysis of human erythrocytes at 200 MPa were examined by changing intracellular pH (7.2-7.9). These inhibitors suppressed the hemolysis at neutral pH but enhanced it at alkaline pH. However, such an enhancement was suppressed by cross-linking of membrane proteins using diamide. From the near-UV CD spectra of band 3 and the relation between hemolysis and anion transport in intact or trypsin-treated erythrocytes, it was found that such hemolytic properties were characterized by the binding of inhibitors to band 3. In addition, spectrin detachment from the erythrocyte membrane by high pressure was considerably suppressed by DIDS treatment at neutral pH, but not by DIDS labeling at alkaline pH. These results suggest that the interaction of the cytoplasmic domain of band 3 with the cytoskeleton, which is induced by the binding of ligands to the exofacial domain of band 3, is dependent on the intracellular pH, i.e., the linking is tightened at neutral pH but relaxed at alkaline pH.
通过改变细胞内pH值（7.2 - 7.9），研究了阴离子转运抑制剂如4,4'-二异硫氰基芪-2,2'-二磺酸盐（DIDS）和4-乙酰氨基-4'-异硫氰基芪-2,2'-二磺酸盐对200 MPa下人红细胞溶血的影响。这些抑制剂在中性pH值时抑制溶血，但在碱性pH值时增强溶血。然而，使用二酰胺交联膜蛋白可抑制这种增强作用。从带3的近紫外圆二色光谱以及完整或胰蛋白酶处理的红细胞中溶血与阴离子转运之间的关系发现，这种溶血特性的特征在于抑制剂与带3的结合。此外，在中性pH值下用DIDS处理可显著抑制高压导致的血影蛋白从红细胞膜上脱离，但在碱性pH值下进行DIDS标记则无此作用。这些结果表明，带3胞质结构域与细胞骨架的相互作用，这种相互作用由配体与带3胞外结构域的结合所诱导，取决于细胞内pH值，即这种连接在中性pH值时收紧，而在碱性pH值时松弛。
