Description

LL-37

Synthetic antimicrobial peptide from the human cathelicidin family for in vitro research on membranotropic interactions, immunomodulation, and cell migration

Overview & Mechanism of Action (In Vitro)

LL-37 is a synthetic amphiphilic helical peptide consisting of 37 amino acids with the sequence (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES). It represents the functional C-terminal cleavage product of the human pro-peptide hCAP-18 (human cathelicidin). In cellular biology, microbiology, and immunology, it serves as a fundamental model for studying non-specific innate immunity and epithelial barrier modulation:

• Membranotropic & Lytic Mechanisms: Formation of an amphiphilic α-helix in the presence of negatively charged phospholipid membranes. Investigation of lipid bilayer disruption mechanisms (toroidal pores, carpet model) across Gram-positive and Gram-negative bacterial membrane models.
• Immunomodulation & Endotoxin Neutralization: High-affinity binding to bacterial lipopolysaccharides (LPS), inhibiting LPS-induced TLR4 signaling pathway activation and downregulating pro-inflammatory cytokine release in macrophage models.
• Chemotaxis & Cellular Motility Stimulation: Activation of the G-protein coupled receptor FPR2 (Formyl Peptide Receptor 2 / FPRL1) and purinergic P2X7 receptors, promoting directed migration of keratinocytes, endothelial cells, and fibroblasts in wound healing assays.

Technical & Chemical Specifications

• Classification: Research Antimicrobial Peptide (AMP) / Human Cathelicidin Fragment
• Amino Acid Sequence: Leu-Leu-Gly-Asp-Phe-Phe-Arg-Lys-Ser-Lys-Glu-Lys-Ile-Gly-Lys-Glu-Phe-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-Asn-Leu-Val-Pro-Arg-Thr-Glu-Ser
• Form: Sterile lyophilized white powder (cake)
• Molecular Weight Identification: Confirmed via Mass Spectrometry (MS)
• Recommended Reconstitution Solvent: Sterile bacteriostatic water, sterile deionized water, or physiological saline (low-protein-binding containers recommended to prevent peptide adherence to glass/plastic surfaces; avoid repeated freeze-thaw cycles)
• Storage Conditions: Store long-term at -20 °C in a dry, dark environment. Following reconstitution, keep refrigerated at 2–8 °C and utilize within standard experimental protocol timelines.

Scientific References & Literature

• Dürr, U. H., et al. LL-37, the only human member of the cathelicidin family of antimicrobial peptides: Structure, function, and clinical implications. Biochimica et Biophysica Acta (BBA) – Biomembranes, 2006.
• Koczulla, R., et al. An angiogenic role for the human peptide antibiotic LL-37/hCAP-18 in model endothelial systems. Journal of Clinical Investigation, 2003.
• Vandamme, D., et al. Antimicrobial peptides: Mechanisms of action and resistance in in vitro models. Antimicrobial Agents and Chemotherapy, 2012.
• De Yang, et al. LL-37, the neutrophil granule- and epithelial cell-derived cathelicidin, utilizes formyl peptide receptor-like 1 (FPRL1) as a receptor to chemoattract cells. The Journal of Experimental Medicine, 2000.

Legal Disclaimer & Terms of Purchase

This product is classified and supplied strictly for laboratory, scientific, and in vitro research purposes only (Research Use Only – RUO). This compound is not a drug, medicine, dietary supplement, cosmetic product, or substance intended for human or veterinary consumption, direct administration, injection, or diagnostic procedures.

By placing an order, the purchaser explicitly confirms that they are at least 18 years of age, possess the requisite professional qualifications and laboratory equipment to safely handle research materials, and are fully conversant with all relevant safety protocols for managing research substances. The seller assumes no liability for any use contrary to these terms.