LL-37 (Cathelicidin) is a cationic, amphipathic peptide belonging to the cathelicidin family of antimicrobial peptides. It is the only cathelicidin-derived antimicrobial peptide found in humans. Preclinical research has identified LL-37 as a critical component of the innate immune system, functioning as a first line of defense against pathogens. Beyond its direct antimicrobial properties, studies investigate its role as a potent immune modulator, influencing chemotaxis (cell migration) and cytokine release. It is frequently researched in the context of biofilm disruption and tissue re-epithelialization. Supplied as a lyophilized powder strictly for laboratory research.

Area of Interest

Research on LL-37 has focused on immunological and microbial pathways:

• Biofilm Disruption: Investigated for its ability to penetrate and degrade bacterial biofilms, a primary mechanism of resistance in chronic infections (such as P. aeruginosa and S. aureus).
• Wound Repair Signaling: Studies examine its role in promoting angiogenesis (blood vessel formation) and keratinocyte migration, suggesting a function in the mechanical repair of tissue.
• Immune Modulation: Research focuses on its ability to neutralize endotoxins (LPS) and recruit immune cells (neutrophils and monocytes) to sites of infection without triggering excessive inflammation.
• Gut Homeostasis: Preclinical models explore its expression in the colonic mucosa and its potential role in maintaining the barrier against pathogenic gut flora.

These properties make LL-37 a primary reagent for laboratories investigating antibiotic resistance, chronic wound pathology, and intestinal microbiome dynamics.

Technical Information

• Chemical Name: LL-37 (Cathelicidin Antimicrobial Peptide)
• Synonyms: CAMP, hCAP-18 fragment
• Molecular Formula: C₂₀₅H₃₄₀N₆₀O₅₃
• Molecular Weight: 4493.3 g/mol
• Sequence: Leu-Leu-Gln-Asp-Phe-Phe-Arg-Asn-Lys-Ser-Lys-Lys-Ile-Gln-Gly-Glu-Lys-Leu-Lys-Lys-Asp-Arg-Ile-Arg-Asn-Thr-Ala-Ile-Arg-Asn-Leu-Ile-Gly-Arg-Ile-Ala-Leu
• CAS Number: 154947-66-7
• Peptide Classification: Antimicrobial Peptide (AMP) / Host Defense Peptide

Storage Guidelines

• Lyophilized peptide is stable at room temperature for several weeks.
• For long-term storage, keep at −20°C or below.

• Once reconstituted, store at 2–8 °C. Use within 2-3 weeks as LL-37 can be susceptible to aggregation in solution.

Solubility

LL-37 is soluble in sterile water or saline. Due to its amphipathic nature, it may foam easily; reconstitute by directing the liquid down the side of the vial and swirling gently.

References

• Nijnik, A., & Hancock, R. E. (2009). “The roles of cathelicidin LL-37 in immune defence and novel clinical applications.” Current Opinion in Hematology, 16(1), 41–47. https://doi.org/10.1097/MOH.0b013e32831ac517
• Gallo, R. L., et al. (2002). “Antimicrobial peptides: an emerging concept in cutaneous biology.” Journal of Investigative Dermatology, 118(1), 402–408. https://doi.org/10.1046/j.0022-202x.2001.01666.x
• Overhage, J., et al. (2008). “Human host defense peptide LL-37 prevents bacterial biofilm formation.” Infection and Immunity, 76(9), 4176–4182. https://doi.org/10.1128/IAI.00311-08

Certificate of Analysis (COA): Available here