L-Theanine has favorable physiological effects in terms of human health, but the mechanisms that transport it to its target organs or cells are not completely defined. To identify the major transport mechanisms of L-theanine, we screened for candidate transporters of L-3H-theanine in several mammal cell lines that intrinsically express multiple transporters with various specificities. All of the cells tested, T24, HepG2, COS1, 293A, Neuro2a, and HuH7, absorbed L-3H-theanine. Uptake was significantly inhibited by the addition of L-leucine and by a specific inhibitor of the system L transport system, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). L-3H-Theanine uptake occurred mostly independently of Na+. These results indicate that L-theanine was taken up via a system L like transport system in all of the cells tested. Additionally, in experiments using cells stably expressing two system L isoforms, LAT1 and LAT2, we found that the two isoforms mediated L-theanine transport to similar extents. Taken together, our results indicate that L-theanine is transported mostly via the system L transport pathway and its isoforms.

中文翻译：

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L型氨基酸转运蛋白参与茶氨酸转运。

L-茶氨酸在人类健康方面具有良好的生理作用，但是将L-茶氨酸转运至其靶器官或细胞的机制尚未完全确定。为了确定L-茶氨酸的主要转运机制，我们在几种哺乳动物细胞系中筛选了L-3H-茶氨酸的候选转运蛋白，这些细胞系固有地表达具有多种特异性的多种转运蛋白。所有测试的细胞，T24，HepG2，COS1、293​​A，Neuro2a和HuH7，都吸收了L-3H-茶氨酸。通过添加L-亮氨酸和系统L转运系统的特定抑制剂2-氨基双环-（2,2,1）-庚烷-2-羧酸（BCH）可以显着抑制摄取。L-3H-茶氨酸的摄取主要独立于Na +发生。这些结果表明，在所有测试的细胞中，L-茶氨酸通过类似运输系统的系统L吸收。此外，在使用稳定表达两种系统L亚型LAT1和LAT2的细胞进行的实验中，我们发现这两种亚型介导L-茶氨酸转运的程度相似。两者合计，我们的结果表明，L-茶氨酸主要通过系统L转运途径及其同工型转运。