ROLE OF TRYPTOPHAN ON HEPATIC PROTEIN SYNTHESIS

这项研究的目的是探索一个单一的基本要素 氨基酸，特别是L-色氨酸，影响蛋白质代谢， 肝脏 在我们实验室的早期报告中，我们已经描述了， L-色氨酸快速刺激肝多聚核糖体聚集， 蛋白质合成 这种影响似乎与以下因素的改变有关： 转录和转录后控制。 早期研究 在细胞和亚细胞水平上的研究表明， 作用于肝核（核膜），刺激增强 mRNA的核质易位最近的研究结果表明， 在核膜上有一个特定的结合位点 老鼠的肝脏 这种64 kDa的L-色氨酸糖蛋白受体具有 进行了纯化和表征。 我们计划进一步描述 （组成、活性结构和功能）64 kDa糖蛋白 纯化为肝核膜色氨酸结合蛋白。 这将使用纯化的大鼠肝核膜进行 色氨酸结合蛋白以及使用克隆的融合蛋白。 以来 色氨酸快速刺激肝细胞核多聚腺苷酸聚合酶活性 由于我们已经确定了这种酶与 色氨酸受体蛋白，我们计划确定 两人之间 我们认为色氨酸与受体结合， 由于色氨酸的增加，聚（A）聚合酶的活性增强， 重要的和至关重要的组成部分，在罗汉诱导的刺激， 肝脏蛋白质合成 这些信息可以提供基本的见解， 一种重要的饮食成分，如L-色氨酸， 可能在哺乳动物肝脏蛋白质代谢中起调节作用。

This investigation is interested in exploring how a single essential amino acid, specifically L-tryptophan, affects protein metabolism in the liver. In earlier reports from our laboratory, we have described that L-tryptophan rapidly stimulates hepatic polyribosomal aggregation and protein synthesis. This effect appears to be related to alterations in both transcriptional and posttranscriptional controls. Earlier studies at the cellular and subcellular levels have revealed that L-tryptophan acts on the hepatic nucleus (nuclear membrane) to stimulate enhanced nucleocytoplasmic translocation of mRNA Recent findings have demonstrated that there is a specific tryptophan-binding site on the nuclear envelopes of rat liver. This 64 kDa glycoprotein receptor for L-tryptophan has been purified and characterized. We plan to further characterize (composition, active structure and function) the 64 kDa glycoprotein purified as the hepatic nuclear envelope tryptophan binding protein. This will be conducted using purified rat hepatic nuclear envelope tryptophan binding protein as well as using cloned fusion protein. Since tryptophan rapidly stimulates hepatic nuclear poly(A)polymerase activity and since we have determined a close association between this enzyme and the tryptophan receptor protein, we plan to define the relationship between the two. We consider the receptor binding of tryptophan and the enhancement of poly(A)polymerase activity due to tryptophan to be important and vital components in the tryptophan-induced stimulation of hepatic protein synthesis. Such information may offer basic insight as to how an important dietary component, as exemplified by L-tryptophan, may play a regulatory role in mammalian liver protein metabolism.