HLopt2 peptide

HLopt2 peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

H-CFQWKRAMRKVR-OH

H-Cys-Phe-Gln-Trp-Lys-Arg-Ala-Met-Arg-Lys-Val-Arg-OH

12

95.2%

C₇₁H₁₁₇N₂₅O₁₄S₂

1608.97

Synthetic

Powder

Owing to the increasing number of infections in hospitalised patients caused by resistant strains of fungi, there is a need to develop new therapeutic agents for these infections. Naturally occurring antimicrobial peptides may constitute models for developing such agents. A modified peptide sequence (CFQWKRAMRKVR; HLopt2) based on amino acid residues 20–31 of the N-terminal end of human lactoferrin (hLF) as well as a double-sized human lactoferricin-like peptide (amino acid residues 16–40; HLBD1) were investigated for their antifungal activities in vitro and in vivo. By in vitro assay, HLopt2 was fungicidal at concentrations of 12.5–25 μg/mL against Cryptococcus neoformans, Candida albicans, Candida krusei, Candida kefyr and Candida parapsilosis, but not against Candida glabrata. HLopt2 was demonstrated to have ≥16-fold greater killing activity than HLBD1. By inducing some helical formation caused by lactam bridges or by extending the assay time (from 2 h to 20 h), HLBD1 became almost comparable with HLopt2 in its fungicidal activity. Killing of C. albicans yeast cells by HLopt2 was rapid and was accompanied by cytoplasmic and mitochondrial membrane permeabilisation as well as formation of deep pits on the yeast cell surface. In a murine C. albicans skin infection model, atopic treatment with the peptides resulted in significantly reduced yields of Candida from the infected skin areas. The antifungal activities of HLopt2 in vitro and in vivo suggest possible potential as a therapeutic agent against most Candida spp. and C. neoformans. The greatly improved antifungal effect of the lactam-modified HLBD1 indicates the importance of amphipathic helix formation for lethal activity.

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

• Kondori N, Baltzer L, Dolphin GT, Mattsby-Baltzer I. Fungicidal activity of human lactoferrin-derived peptides based on the antimicrobial u03b1u03b2 region. Int J Antimicrob Agents. 2011;37(1):51u201357. doi:10.1016/j.ijantimicag.2010.08.020

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.