The hemoglobin alpha chain [106-141] peptide is a fragment derived from the C-terminal region of the alpha globin subunit. This sequence encompasses amino acids 106 to 141 of the mature alpha chain. In both bovine and human hemoglobin, this region is highly conserved and includes the pentapeptide TSKYR (positions 137-141), known as neokyotorphin. The peptide is hydrophilic and has a molecular mass of approximately 653 Da. It is generated through enzymatic hydrolysis, such as with pepsin under acidic conditions, following a sequential 'zipper' mechanism where the globin chains are progressively cleaved into smaller fragments.

This peptide fragment possesses several intrinsic bioactive properties. The core TSKYR sequence exhibits antimicrobial, antioxidant, and opioid activities. Studies indicate that the peptide is a final product of hydrolysis, accumulating during the reaction and remaining resistant to further degradation under specific conditions. Its production is rapid and proportional to the initial hemoglobin concentration, highlighting its stability and the efficiency of its release from the parent protein.

• Mak P, Wójcik K, Wicherek L, Suder P, Dubin A. Antibacterial hemoglobin peptides in human menstrual blood. Peptides. 2004;25(11):1839-47.
• Outman A, Deracinois B, Flahaut C, Diab MA, Gressier B, Eto B, Nedjar N. Potential of Human Hemoglobin as a Source of Bioactive Peptides: Comparative Study of Enzymatic Hydrolysis with Bovine Hemoglobin and the Production of Active Peptide α137-141. Int J Mol Sci. 2023 Jul 25;24(15):11921. doi: 10.3390/ijms241511921. PMID: 37569300; PMCID: PMC10418852.

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。