Species differences in nucleoside transport. A study of uridine transport and nitrobenzylthioinosine binding by mammalian erythrocytes.
Species differences in nucleoside transport. A study of uridine transport and nitrobenzylthioinosine binding by mammalian erythrocytes.
复制标题
核苷转运的物种差异。
作者：
S. Jarvis;J. Hammond;A. Paterson;A. Clanachan
尿苷在兔、人、小鼠、大鼠和豚鼠红细胞内转运的动力学研究表明，这一过程的表观Km在这些细胞类型中相似（约0.2mM），但Vmax不同。价值观差异明显。在这一系列细胞类型中，Vmax.值与每种类型的细胞中存在的转运抑制性高亲和力结合位点的数目成比例。在犬红细胞中未检测到尿苷或腺苷的转运，也未证实可饱和、高亲和力的硝基苄基硫代肌苷结合。这些研究结果表明，核苷转运能力的物种差异是由于功能性核苷转运位点的细胞表面含量的差异，而不是这些位点的动力学性质的差异。
A kinetic study of the inward transport of uridine in erythrocytes of rabbit, human, mouse, rat and guinea-pig demonstrated that the apparent Km of this process was similar (about 0.2mM) in these cell types, but Vmax. values differed markedly. In this array of cell types, Vmax. values were proportional to the number of transport-inhibitory, high-affinity binding sites present per cell of each type. Transport of uridine or adenosine was not detected in dog erythrocytes, nor was saturable, high-affinity binding of nitrobenzylthioinosine demonstrable. These findings demonstrate that species differences in nucleoside transport capacity are attributable to differences in the cell-surface content of functional nucleoside transport sites, rather than to differences in the kinetic properties of these sites.