Nutritional Evaluation of Glycated Valine and Tryptophan as a Precursor for Protein Synthesis in Chicken Embryo Myoblasts
Nutritional Evaluation of Glycated Valine and Tryptophan as a Precursor for Protein Synthesis in Chicken Embryo Myoblasts
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DOI：
10.2141/jpsa.0150016
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发表时间：
2015-10-01
影响因子：
1.5
通讯作者：
Kita, Kazurni
中科院分区：
文献类型：
--
作者：
Makino, Ryosuke;Sugahara, Misaki;Kita, Kazurni
缬氨酸和色氨酸是蛋白质合成的前体。糖基化是一种非酶反应，导致葡萄糖的羰基和氨基酸的α-氨基之间的脱水缩合。色氨酸的糖基化形成两种糖化化合物，Amadori产物和(1R，3S)-1-(D-葡萄糖-1，2，3，4，5-pentahydroxypentyl)-1，2，3，4-tetrahydro-8-carboline-3-carboxylic酸)。在Valine容易形成的情况下，只有Amadori产物通过糖基化形成。这些化合物缺乏α-氨基，这可能不会使糖化氨基酸成为蛋白质合成的前体。众所周知，鸡的糖基化比哺乳动物更容易进行，因为高血糖和高体温是禽类的特征。因此，在这项研究中，我们试图评估糖化缬氨酸和色氨酸作为蛋白质合成前体的营养价值。鸡胚成肌细胞在添加或不添加胰岛素样生长因子-I(IGF-I)的Valine或无色氨酸的培养液中培养。在该细胞培养体系中，比较了在缺乏缬氨酸的培养液中添加葡萄糖-缬氨酸Amadori产物的效果，并与添加valine的效果进行了比较。还检测了补充PHP-THβC的效果。用放射性示踪剂[H-3]-苯丙氨酸测定成肌细胞的蛋白质合成和降解。在缺乏缬氨酸的培养液中添加葡萄糖-缬氨酸Amadori产物不影响鸡胚成肌细胞的蛋白质合成。在缺乏色氨酸的培养液中加入IGF-I和PHP-THβC可增加鸡胚成肌细胞的蛋白质合成，但提高的幅度低于在缺乏色氨酸的培养液中添加色氨酸的水平。在没有IGF-I的情况下，PHP-THβC不能增加蛋白质的合成。这些结果表明，Valine-葡萄糖Amadori产物和PHP-THβC不具有作为蛋白质合成前体的营养价值。
Valine and Tryptophan play a role of being a precursor for protein synthesis. Glycation is a non-enzymatic reaction causing dehydrating condensation between the carbonyl group of glucose and the alpha-amino group of amino acids. Glycation of tryptophan forms two types of glycated compounds, Amadori product and (1R,3S)-1-(D-gluco-1, 2,3,4,5-pentahydroxypentyl)-1,2,3,4-tetrahydro-8-carboline-3-carboxylic acid (PHP-TH beta C). In ease of valine, only Amadori product is formed by glycation. These compounds are lack of the alpha-amino group, which might not make glycated amino acids be a precursor for protein synthesis. It is known that glycation proceeds more readily in chickens than in mammals because hyperglycemia and high body temperature are features in avian species. In this study, therefore, we attempted to evaluate nutritional value of glycated valine and tryptophan as a precursor for protein synthesis. Myoblasts from chicken embryos were incubated in valine or tryptophan-free medium supplemented with or without insulin-like growth factor-I (IGF-I). In this cell culture system, the effect of glucose-valine Amadori product supplemented in the valine deficient medium was compared to that of supplemented valine. The effect of PHP-TH beta C supplementation, was also examined. Protein synthesis and degradation of myoblasts were measured using a radioactive tracer, [H-3]-phenylalanine. Protein synthesis of chicken embryo myoblasts was not affected by the addition of glucose-valine Amadori product into valine-deficient medium. When IGF-I was added in the medium, and the addition of PHP-TH beta C into tryptophan-deficient medium increased protein synthesis of chicken embryo myoblasts, but the extent of elevation of protein synthesis was lower than that in case of tryptophan supplementation into.tryptophan-deficient medium. In the absence of IGF-I, PHP-TH beta C did not increase protein synthesis. These results suggest that valine-glucose Amadori product and PHP-TH beta C does not have nutritional value for being a precursor of protein synthesis.