Schuldiner S, Maron R, Kanner B I
Monogr Neural Sci. 1980;7:117-28. doi: 10.1159/000388819.
Chromaffin granule membrane vesicles accumulate large amounts of catecholamines against their concentration gradients. This process is ATP-dependent, reserpine, FCCP and nigericin sensitive. Carrier-mediated, reserpine-sensitive accumulation has also been demonstrated in the absence of ATP when a pH gradient (delta pH) is artificially generated across the membrane. Crude preparation of 5-hydroxytryptamine storage vesicles from rat brain or from pig platelets showed similar requirement of a transmembrane pH gradient for accumulation of the amine. The catecholamine transporter from chromaffin granules has been solubilized by the use of detergents in the presence of phospholipids. Removal of the detergent either by Sephadex filtration or by dialysis results in the formation of proteoliposomes which catalyze delta pH-dependent, reserpine-sensitive catecholamine accumulation. Under proper conditions, the solubilized H+-translocating ATPase has been incorporated into the same proteoliposomes with the catecholamine transporter, and ATP-dependent transport has been measured. The reconstituted protein shows specificity and affinity towards catecholamines similar to the native one.
嗜铬粒膜囊泡逆浓度梯度积累大量儿茶酚胺。此过程依赖ATP，对利血平、FCCP和尼日利亚菌素敏感。当人工在膜上产生pH梯度（ΔpH）时，在无ATP的情况下也已证明存在载体介导的、对利血平敏感的积累。从大鼠脑或猪血小板中粗制5-羟色胺储存囊泡，显示出积累胺时对跨膜pH梯度有类似要求。嗜铬粒中的儿茶酚胺转运体已通过在磷脂存在下使用去污剂进行溶解。通过Sephadex过滤或透析去除去污剂会导致形成蛋白脂质体，其催化依赖ΔpH的、对利血平敏感的儿茶酚胺积累。在适当条件下，已将溶解的H⁺转运ATP酶与儿茶酚胺转运体一起整合到同一蛋白脂质体中，并测量了依赖ATP的转运。重构的蛋白质对儿茶酚胺显示出与天然蛋白质相似的特异性和亲和力。
