KR-12 (human) 多肽 (TFA已除)

KRIVQRIKDFLR-NH2

H-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-NH2

12

95.8

C₇₁H₁₂₇N₂₅O₁₅

1570.93

1218951-51-9

固相合成

KR-12 peptide is derived from the human antimicrobial peptide LL-37, and corresponds to its amino acid residues 18-29. It retains the antimicrobial activity of LL-37 while showing low toxicity to human cells, making it a potential candidate for various applications, especially in cosmetics.

KR-12 peptide has a nearly perfect amphipathic α -helical structure. This unique structure endows it with strong antimicrobial properties. It can effectively inhibit the growth of a wide range of bacteria and yeast. Its minimal inhibitory concentration (MIC) values against different strains are impressively low, much lower than those of common cosmetic preservatives like methylparaben and Scutellaria baicalensis extract. When incorporated into cosmetic formulations, KR-12 peptide exhibits excellent bactericidal effects. It can kill gram - negative Escherichia coli at concentrations starting from 25 μg/mL and gram - positive Staphylococcus aureus at 100 μg/mL, while conventional preservatives show no significant bactericidal activity even at higher concentrations.

Moreover, KR-12 peptide shows very low cytotoxicity to mammalian cells. In MTT assays with RAW264.7 cells, it demonstrated negligible toxicity even at relatively high concentrations. This makes it a safe and effective alternative to traditional cosmetic preservatives, offering a new solution for ensuring the stability of cosmetic products without causing harm to the human body.

一般情况下， KR-12 (human) 多肽 (TFA已除) 粉末应该保存在-20甚至-70摄氏度. KR-12 (human) 多肽 (TFA已除) 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

• Yun, H., Min, H.J. & Lee, C.W. NMR structure and bactericidal activity of KR-12 analog derived from human LL-37 as a potential cosmetic preservative. J Anal Sci Technol 11, 14 (2020). https://doi.org/10.1186/s40543-020-00213-x
• Kamysz E, Sikorska E, Jaśkiewicz M, Bauer M, Neubauer D, Bartoszewska S, Barańska-Rybak W, Kamysz W. Lipidated Analogs of the LL-37-Derived Peptide Fragment KR12-Structural Analysis, Surface-Active Properties and Antimicrobial Activity. Int J Mol Sci. 2020 Jan 30;21(3):887. doi: 10.3390/ijms21030887. PMID: 32019109; PMCID: PMC7036753.
• Jacob B, Park IS, Bang JK, Shin SY. Short KR-12 analogs designed from human cathelicidin LL-37 possessing both antimicrobial and antiendotoxic activities without mammalian cell toxicity. J Pept Sci. 2013 Nov;19(11):700-7. doi: 10.1002/psc.2552. Epub 2013 Sep 17. PMID: 24105706.
• Mishra B, Epand RF, Epand RM, Wang G. Structural location determines functional roles of the basic amino acids of KR-12, the smallest antimicrobial peptide from human cathelicidin LL-37. RSC Adv. 2013 Nov 14;(42):10.1039/C3RA42599A. doi: 10.1039/C3RA42599A. PMID: 24307932; PMCID: PMC3844289.

三氟乙酸（TFA）是一种强酸，常用于从固相树脂中裂解合成的多肽，也可用于提高多肽纯化步骤中的HPLC性能。默认情况下，定制的多肽是以冻干的TFA盐的形式交付的，其中TFA的含量可能高达10-45%。

定制多肽中的TFA可能会导致后续检测数据出现无法解释的差异。例如，nM浓度的TFA已被证明会干扰细胞实验，在某些情况下会抑制细胞增殖，而在其他情况下会增加细胞活力。

TFA去除服务推荐用于:

• 将用于细胞试验的多肽
• 将被用作原料药或制成品的多肽
• 含有大量碱性残基的亲水多肽

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。