Matsuyama H, Kawano Y, Hamasaki N
J Biol Chem. 1983 Dec 25;258(24):15376-81.
Extracellular treatment of human erythrocytes with papain completely converted the chymotryptic 38,000-dalton fragment of Band 3 to the 29,000-dalton fragment and inhibited the transport of inorganic phosphate in the cells. The inhibition, however, was not complete, indicating the presence of two components in the anion-transport system: the one resistant to papain digestion and the other sensitive to the digestion. The latter activity is well correlated with the degradation of the 38,000-dalton fragment. The activity remaining in the cells treated with papain was markedly different from that of the control cells. The remaining activity was not inhibited by pyridoxal phosphate and dinitrostilbene-2,2'-disulfonic acid, potent inhibitors to the anion transport, whereas phenyl phosphate inhibited the activities of both papain-treated and control cells. The results indicate that the anion-transport system consists of multiple anion-binding sites and a part of the system which is sensitive to pyridoxal phosphate and dinitrostilbene-2,2'-disulfonic acid was located in the papain-sensitive portion of 38,000-dalton fragment. A possible model of the anion-transport system was presented.
用木瓜蛋白酶对人红细胞进行细胞外处理，可使带3的胰凝乳蛋白酶作用产生的38000道尔顿片段完全转化为29000道尔顿片段，并抑制细胞中无机磷酸的转运。然而，这种抑制并不完全，这表明阴离子转运系统中存在两种成分：一种对木瓜蛋白酶消化有抗性，另一种对消化敏感。后一种活性与38000道尔顿片段的降解密切相关。用木瓜蛋白酶处理的细胞中剩余的活性与对照细胞的活性明显不同。剩余活性不受阴离子转运的有效抑制剂磷酸吡哆醛和二硝基芪-2,2'-二磺酸的抑制，而磷酸苯酯则抑制木瓜蛋白酶处理细胞和对照细胞的活性。结果表明，阴离子转运系统由多个阴离子结合位点组成，对磷酸吡哆醛和二硝基芪-2,2'-二磺酸敏感的系统部分位于38000道尔顿片段的木瓜蛋白酶敏感部分。提出了阴离子转运系统的一种可能模型。
