Goto R, Tamemasa O
Radioisotopes. 1980 Jan;29(1):1-6. doi: 10.3769/radioisotopes.29.1.
The present investigation was undertaken to examine an evidence for the exchange diffusion of D-leucine as well as L-leucine and further to study the effect of temperature reduction on the exchange diffusion, in Ehrlich ascites tumor cells in vitro. The homoexchange diffusion for D-leucine was observed at 37 degrees C, the extent being nearly equal to that for L-leucine. The heteroexchange diffusion between D- and L-leucines also occurred at 37 degrees C. These findings were compatible with an assumption that there is a common pathway for D- and L-leucine transport in the tumor cells. It was demonstrated that the exchangeability of D-leucine was depressed remarkably at 0 degree C, while L-leucine still had a considerable exchangeability. This difference in exchangeability of D- and L-leucines in temperature reduction seems to reflect that the bulky hydrocarbon side chains of both the isomers are bound to the different site of carrier as described in the preceding paper.
本研究旨在检测 Ehrlich 腹水瘤细胞体外 D-亮氨酸和 L-亮氨酸交换扩散的证据，并进一步研究降温对交换扩散的影响。在 37℃观察到 D-亮氨酸的同型交换扩散，其程度与 L-亮氨酸的几乎相等。D-亮氨酸和 L-亮氨酸之间的异型交换扩散也发生在 37℃。这些发现与肿瘤细胞中 D-亮氨酸和 L-亮氨酸转运存在共同途径的假设相符。结果表明，在 0℃时 D-亮氨酸的交换能力显著降低，而 L-亮氨酸仍具有相当的交换能力。D-亮氨酸和 L-亮氨酸在降温时交换能力的这种差异似乎反映了如前文所述，两种异构体的庞大烃侧链与载体的不同位点结合。
