You may also need the inactive scrambled control peptide:11R-VEET peptide

The 11R-VIVIT peptide is a synthetic cell-penetrating construct designed to interfere with the interaction between the calcium-dependent phosphatase calcineurin and the nuclear factor of activated T cells (NFAT) transcription factors. It consists of an 11-arginine (11R) transduction domain linked via a three-glycine spacer to the high-affinity VIVIT sequence (MAGPHPVIVITGPHEE), which mimics the PxIxIT motif found in NFAT proteins. This motif serves as the major docking site for calcineurin on NFAT, and the VIVIT sequence was optimized through affinity-driven selection from combinatorial peptide libraries to bind calcineurin with greater strength than the native NFATc2 motif (PRIEIT). The 11R sequence facilitates translocation across cellular membranes, enabling the peptide to target intracellular signaling pathways.

In glioma cells, which predominantly express NFATc3, 11R-VIVIT unexpectedly activates NFAT signaling rather than inhibiting it. This is evidenced by increased NFAT-dependent promoter activity, upregulated expression of endogenous NFAT-target genes such as COX2 and c-MYC, and translocation of NFAT proteins from the cytoplasm to the nucleus. This aberrant activation may stem from the presence of two calcineurin docking sites in NFATc3 (a PxIxIT motif and an additional LxVP motif), allowing calcineurin to still interact with NFAT through the LxVP site while the PxIxIT site is blocked by the VIVIT peptide. The spherical structure of a GFP tag in VIVIT-GFP fusion proteins may sterically hinder access to both docking sites, explaining why that construct inhibits NFAT signaling, whereas the linear 11R-VIVIT does not.

• Zhang L, Li R, Shi W, Liang X, Liu S, Ye Z, Yu C, Chen Y, Zhang B, Wang W, Lai Y, Ma J, Li Z, Tan X. NFAT2 inhibitor ameliorates diabetic nephropathy and podocyte injury in db/db mice. Br J Pharmacol. 2013 Sep;170(2):426-39. doi: 10.1111/bph.12292. PMID: 23826864; PMCID: PMC3834765.
• Ellert-Miklaszewska A, Szymczyk A, Poleszak K, Kaminska B. Delivery of the VIVIT Peptide to Human Glioma Cells to Interfere with Calcineurin-NFAT Signaling. Molecules. 2021 Aug 7;26(16):4785. doi: 10.3390/molecules26164785. PMID: 34443374; PMCID: PMC8400789.

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。