LL-37

LL-37

LL-37 is a 37-amino acid cationic antimicrobial peptide (AMP) and the only known human cathelicidin, derived from the C-terminal domain of the precursor protein hCAP-18 (human cationic antimicrobial protein 18). It is produced by neutrophils, macrophages, mast cells, NK cells, and epithelial cells of the skin, lung, and gastrointestinal tract, and represents a key component of the innate immune system’s first-line defence against microbial pathogens. LL-37 has been extensively studied for its broad-spectrum antimicrobial activity, immunomodulatory functions, wound healing properties, and roles in cancer biology and autoimmune disease.

Mechanism of Action

LL-37 exerts antimicrobial activity primarily through membrane disruption: its amphipathic α-helical structure enables insertion into bacterial, fungal, and viral lipid membranes, forming pores or inducing membrane lysis via a carpet or toroidal pore mechanism. Beyond direct microbicidal activity, LL-37 modulates innate immune signalling by binding to and neutralising LPS (lipopolysaccharide) and LTA (lipoteichoic acid), preventing TLR4/TLR2-mediated inflammatory cascades. It also acts as a chemoattractant for neutrophils, monocytes, and T cells via FPRL1 receptor activation, promotes angiogenesis through EGFR and VEGFR signalling, and stimulates keratinocyte migration and proliferation — supporting its investigation in wound healing and tissue repair research.

Research Applications

• Antimicrobial peptide (AMP) mechanism, membrane disruption, and pore formation studies
• Innate immune modulation, LPS neutralisation, and TLR signalling research
• Wound healing, keratinocyte migration, and angiogenesis investigation
• Cathelicidin biology and host defence peptide research
• Cancer biology, autoimmune disease, and inflammatory signalling models

Specifications

• Molecular Formula: C₂₀₅H₃₄₀N₆₀O₅₃
• Molecular Weight: 4493.3 g/mol
• CAS Number: 154947-66-7
• Purity: ≥98%
• Form: Lyophilised powder
• Storage: -20°C
• Shelf Life: 24 months

This product is intended for legitimate laboratory and analytical research use only. Not for diagnostic, therapeutic, or consumer use.