Jung C Y, Pinkofsky H B, Cowden M W
Biochim Biophys Acta. 1980 Mar 27;597(1):145-54. doi: 10.1016/0005-2736(80)90158-3.
Two distinct, carrier-mediated glucose uptake processes, a fast, cytochalasin B-sensitive and a slow, cytochalasin B-insensitive flux are identified in parallel in newborn rabbit erythrocytes. The fast, cytochalasin B-sensitive carrier function disappears as rabbits age, and only the slow cytochalasin B-insensitive carrier function is observed with adult rabbit erythrocytes. Three different cytochalasin B binding sites are distinguished in newborn rabbit erythrocytes; a glucose-sensitive site (site I), a cytochalasin E-sensitive site (site II), and a site insensitive to both glucose and cytochalasin E. With adult rabbit erythrocytes, only a cytochalasin E-sensitive site is detected. With glucose-sensitive site disappears as rabbits age, with a time course which is comparable to that of the disappearance of the cytochalasin B-sensitive glucose carrier function. The cytochalasin E-sensitive cytochalasin B binding site does not increase during this change, thus the disappearance of the glucose-sensitive site is not due to its conversion to a cytochalasin E-sensitive site. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of rabbit erythrocyte ghosts revealed a partial decrease in each of the membrane polypeptides of approximate molecular weights of 240 000, 160 000 and 50 000 as rabbits aged. It is concluded that the cytochalasin B-sensitive glucose carrier of fetal rabbit erythrocytes, like that of the human erythrocyte, is tightly associated with the site I cytochalasin B-binding protein, while the cytochalasin B-insensitive glucose carrier, operative in adult rabbit erythrocytes, is not.
在新生兔红细胞中同时发现了两种不同的、载体介导的葡萄糖摄取过程，一种快速的、对细胞松弛素B敏感的过程和一种缓慢的、对细胞松弛素B不敏感的通量。随着兔子年龄的增长，快速的、对细胞松弛素B敏感的载体功能消失，成年兔红细胞中只观察到缓慢的、对细胞松弛素B不敏感的载体功能。在新生兔红细胞中可区分出三种不同的细胞松弛素B结合位点；一个葡萄糖敏感位点（位点I）、一个细胞松弛素E敏感位点（位点II）和一个对葡萄糖和细胞松弛素E均不敏感的位点。对于成年兔红细胞，只检测到一个细胞松弛素E敏感位点。随着兔子年龄的增长，葡萄糖敏感位点消失，其时间进程与细胞松弛素B敏感的葡萄糖载体功能消失的时间进程相当。在此变化过程中，细胞松弛素E敏感的细胞松弛素B结合位点没有增加，因此葡萄糖敏感位点的消失不是由于其转化为细胞松弛素E敏感位点。兔红细胞膜的十二烷基硫酸钠聚丙烯酰胺凝胶电泳显示，随着兔子年龄的增长，分子量约为240 000、160 000和50 000的每种膜多肽都有部分减少。得出的结论是，胎兔红细胞中对细胞松弛素B敏感的葡萄糖载体与人红细胞的一样，与位点I细胞松弛素B结合蛋白紧密相关，而成年兔红细胞中起作用的对细胞松弛素B不敏感的葡萄糖载体则不然。
