KR-12 (human) peptide (TFA removed)

KR-12 (human) peptide (TFA removed)

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

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

Synthetic

Powder

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.

Normally, this peptide will be delivered in lyophilized form and should be stored in a freezer at or below -20 °C. For more details, please refer to the manual: Handling and Storage of Synthetic Peptides

• 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.

Trifluoroacetic acid (TFA) has a significant impact on peptides due to its role in the peptide synthesis process.

TFA is essential for the protonation of peptides that lack basic amino acids such as Arginine (Arg), Histidine (His), and Lysine (Lys), or ones that have blocked N-termini. As a result, peptides often contain TFA salts in the final product.

TFA residues, when present in custom peptides, can cause unpredictable fluctuations in experimental data. At a nanomolar (nM) level, TFA can influence cell experiments, hindering cell growth at low concentrations (as low as 10 nM) and promoting it at higher doses (0.5–7.0 mM). It can also serve as an allosteric regulator on the GlyR of glycine receptors, thereby increasing receptor activity at lower glycine concentrations.

In an in vivo setting, TFA can trifluoroacetylate amino groups in proteins and phospholipids, inducing potentially unwanted antibody responses. Moreover, TFA can impact structure studies as it affects spectrum absorption.