LL-37 5mg

LL-37 — Overview & Chemical Characteristics

LL-37 is a 37–amino-acid cationic antimicrobial peptide (AMP) belonging to the human cathelicidin family and encoded by the CAMP gene. It is produced as part of the innate immune system and plays a central role in host defense, immune signaling, tissue repair, and the regulation of inflammation. LL-37 is the only known cathelicidin in humans, making it a uniquely important molecule in epithelial and immune protection.

LL-37 is generated from its precursor hCAP18, a pro-peptide stored in neutrophil granules and produced by various epithelial and immune cells. During infection or tissue injury, hCAP18 is cleaved to release the active LL-37 fragment, which rapidly interacts with pathogens, host cell membranes, and immune receptors, exhibiting a wide spectrum of biological activities.

Chemical Identity

• CAS Number: 154947-66-7
• Peptide Length: 37 amino acids
• Molecular Formula: C₂₀₅H₃₄₀N₆₀O₅₃
• Molecular Weight: 4493.342 g/mol
• Peptide Class: Antimicrobial peptide (AMP) / human cathelicidin

Structural & Mechanistic Characteristics

Amphipathic α-Helix

LL-37 adopts a long, flexible amphipathic α-helical structure in membrane-like environments. This arrangement presents hydrophobic residues on one face and positively charged residues on the other, allowing the peptide to:

• Insert into microbial lipid bilayers.
• Disrupt membrane organization and integrity.
• Form transient pores or destabilizing curvature in microbial membranes.

These properties underpin LL-37’s broad-spectrum antimicrobial capabilities.

Cationic Charge & Selective Targeting

LL-37 carries a strong net positive charge, which promotes electrostatic attraction to negatively charged components of microbial surfaces such as lipopolysaccharide (LPS) in Gram-negative bacteria and teichoic acids
in Gram-positive organisms. Mammalian cell membranes are comparatively less anionic, which contributes to LL-37’s preferential binding to microbial targets.

Immune Receptor Interactions

In addition to its direct antimicrobial actions, LL-37 functions as an immunomodulatory peptide through interactions with multiple host receptors, including:

• FPR2 (formyl peptide receptor 2): mediates chemotaxis and leukocyte activation.
• P2X7 receptor: contributes to inflammasome and cytokine regulation.
• EGFR transactivation: supports epithelial proliferation and wound repair.
• Toll-like receptors (e.g., TLR4, TLR9): modulates responses to microbial nucleic acids and LPS.

Through these pathways, LL-37 acts as a bridge between innate immunity, inflammation control, and tissue healing.

Primary Biological Functions (Research Context)

Broad-Spectrum Antimicrobial Activity

LL-37 has been shown to exhibit activity against a wide array of microorganisms, including:

• Gram-negative bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa).
• Gram-positive bacteria (e.g., Staphylococcus aureus).
• Fungi such as Candida species.
• Certain enveloped viruses.

Mechanisms include membrane disruption, interference with intracellular targets, and binding/neutralization of bacterial endotoxins such as LPS, which can blunt excessive inflammatory responses.

Immune Modulation & Inflammation Control

LL-37 is also recognized as a powerful immunomodulator. In experimental systems it can:

• Regulate production of pro- and anti-inflammatory cytokines.
• Promote chemotaxis of neutrophils, monocytes, T cells, and other leukocytes.
• Influence dendritic cell maturation and antigen presentation.
• Attenuate LPS-driven inflammatory signaling by directly binding endotoxin.

These activities help maintain a balanced immune response, supporting pathogen clearance while limiting collateral tissue damage.

Wound Healing & Tissue Regeneration

LL-37 contributes to tissue repair processes across skin and mucosal surfaces. Research indicates that it:

• Stimulates epithelial cell migration and proliferation via EGFR-linked signaling.
• Promotes angiogenesis, partly through up-regulation of VEGF.
• Enhances fibroblast activity and extracellular matrix remodeling.
• Accelerates re-epithelialization and wound closure in cutaneous injury models.

Taken together, these effects position LL-37 as a key peptide in models of wound healing and regenerative biology.

Gut Barrier & Mucosal Protection

LL-37 is expressed at various mucosal surfaces, including the gastrointestinal tract, where it:

• Supports the integrity of epithelial tight junctions.
• Helps regulate interactions between the host and the gut microbiota.
• Modulates inflammatory responses during bacterial challenge or barrier disruption.

These properties make LL-37 an important tool in research on inflammatory bowel conditions, epithelial permeability, and mucosal immunity.

Representative Research Applications

In controlled experimental settings, LL-37 is commonly used to explore:

• Host–pathogen interactions – mechanisms of innate defense against bacteria, fungi, and viruses.
• Chronic inflammation and immune dysregulation – including models of colitis, dermatitis, chronic wounds, and airway inflammation.
• Skin health and dermatology – roles in acne, rosacea, psoriasis, and cutaneous barrier function.
• Tissue regeneration and repair – epithelial migration, angiogenesis, and matrix remodeling.
• Gut barrier and microbiome research – epithelial defense, permeability, and host–microbe balance.
• Biofilm formation and disruption – LL-37’s effects on microbial biofilms and surface colonization.

Selected Supporting Studies

1. Studies describing LL-37 as a multifunctional host-defense peptide with antimicrobial and immunomodulatory roles.
2. Work demonstrating LL-37’s involvement in skin immunity, wound healing, and epithelial repair mechanisms.
3. Investigations of LL-37’s impact on gut barrier integrity and inflammatory responses in intestinal models.
4. Research examining LL-37’s role in airway and lung defense against respiratory pathogens.
5. Biofilm-focused studies exploring LL-37’s ability to prevent or disrupt microbial biofilm formation.

NOTICE OF COMPLIANCE

The mission of BioGenix Peptides™ is to provide researchers with the highest-quality, Ultra-Pure Series™ compounds to help unlock the full potential of this evolving field. With precision, purity, and scientific integrity at the core of our operations, BioGenix Peptides™ is dedicated to supporting responsible exploration and discovery.

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