Livagen 多肽

H-KEDA-OH

H-Lys-Glu-Asp-Ala-OH

4

96.9

C₁₈H₃₁N₅O₉

461.46

固相合成

Livagen is a tetrapeptide bioregulator with the sequence Lys-Glu-Asp-Ala. The peptide has shown high biological activity, particularly in experiments with rat liver cells. When exposed to nanomolar concentrations of Livagen, the rate of protein synthesis in hepatocyte cultures from older animals increased significantly, almost reaching the levels characteristic of young rat liver cells. Additionally, Livagen has been found to restore the intracellular circadian rhythm of biosynthesis that is often disrupted by aging.
Livagen's biological activity is of interest due to its potential role in the endogenous opioid system (EOS), which is involved in various physiological functions, including pain sensitivity, emotional reactions, learning capacity, memory, hormone secretion, and the regulation of several body systems such as respiratory, cardiovascular, digestive, and immune systems, as well as thermoregulation. In extreme cases, the EOS can mediate an increase in stress tolerance, preventing the transformation of an acute stress syndrome from a stage of adaptation to a stage of pathogenesis.
The study of Livagen's effects on the EOS focused on its ability to change the activity of enkephalin-degrading enzymes in human serum and to interact with μ- and δ-opioid receptors in the membrane fraction from rat brain. The research found that Livagen inhibits enkephalin-degrading enzymes in human serum more effectively than some well-known peptidase inhibitors, with an IC50 of 20 µM. However, it did not interact with μ- and δ-opioid receptors from the rat brain. This suggests that Livagen's mechanism of action is not through direct interaction with opioid receptors but possibly through the inhibition of enzymes that degrade endogenous opioids, which could make it a promising candidate for treating stress-induced and psychosomatic disorders.

一般情况下， Livagen 多肽 粉末应该保存在-20甚至-70摄氏度. Livagen 多肽 溶解后应该-70摄氏度分装保存，避免反复冻融. 了解更多细节，请查阅手册:多肽溶解及保存指南

• Kost NV, Sokolov OIu, Gabaeva MV, Zolotarev IuA, Malinin VV, Khavinson VKh. Vliianie novykh peptidnykh bioreguliatorov livagena i épitalona na énkefalindegradiruiushchie fermenty syvorotki krovi cheloveka [Effect of new peptide bioregulators livagen and epitalon on enkephalin-degrading enzymes in human serum]. Izv Akad Nauk Ser Biol. 2003 Jul-Aug;(4):427-9. Russian. PMID: 12942748.

三氟乙酸（Trifluoroacetic acid，简称 TFA）是高效液相色谱（简称 HPLC）纯化过程中常用的反离子。TFA 的存在可能会对肽的净重量、外观及溶解度产生影响，具体如下：

对净重量的影响：TFA 盐会增加产物的总质量。在大多数情况下，肽的含量占总重量的 80% 以上，剩余部分则为 TFA。

对溶解度的影响：TFA 盐通常能提高肽在水溶液中的溶解度。

在生物检测中的影响：对于大多数标准的体外检测，残留的 TFA 水平一般不会造成干扰。但需注意，在高灵敏度的细胞研究或生化研究中，需关注其存在可能带来的影响。

干品多肽的重量中不仅仅包含多肽，还包含有一些非肽的组份，如水、被吸收的溶剂、配位离子和盐等。肽的净含量是指肽在其中的重量百分比，这个百分比的数值范围很大，可能从50%到90%，取决于纯度、序列以及合成和纯化的方法，不要将肽的净含量和肽的纯度混为一谈，他们是两个完全不同的概念。纯度通常是通过HPLC测定的。纯度定义的是多肽样品中含正确序列的组分的百分比，而肽的净含量是指样品中肽类物质相对于总物质所占的百分比，肽的净含量通常是氨基酸组分分析或紫外分光法测定的，这个信息主要是在一些对肽的浓度很敏感的实验中，对计算肽的浓度是很重要的。