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LL-37

LL-37 – Cathelicidin Antimicrobial Peptide

At a Glance: LL-37 is a cationic, amphipathic alpha-helical peptide and the only known antimicrobial peptide (AMP) belonging to the human cathelicidin family. What it is used for: It is heavily utilized in laboratory research to study alternatives to traditional antibiotics, innate immune system modulation, and advanced tissue regeneration. By acting as both a direct antimicrobial agent and an immune signaling molecule, researchers use it to observe the eradication of drug-resistant bacteria, biofilm breakdown, and the acceleration of wound-healing pathways in lab rat models.

Product Overview

LL-37 is a naturally occurring, 37-amino acid defense peptide derived from the proteolytic cleavage of the human cationic antimicrobial protein (hCAP18). It serves as a vital front-line component of the innate immune system. Unlike traditional antibiotics that target specific metabolic or enzymatic pathways, LL-37's highly specialized cationic (positively charged) structure allows it to physically bind to and disrupt the negatively charged outer membranes of pathogens. Beyond its direct biocidal capabilities, it is a powerful immunomodulator, making it a critical research compound for studying complex inflammatory responses, extracellular matrix remodeling, and advanced cutaneous wound repair.

Technical Specifications

  • Molecular Formula: C205H340N60O53

  • Molecular Weight: 4493.3 g/mol

  • CAS Number: 154947-66-7

  • Sequence Profile: 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 (37-amino acid sequence)

Mechanism of Action

LL-37 operates through a sophisticated dual-action mechanism, combining direct physical disruption with complex biological signaling:

  • Membrane Permeabilization: Due to its amphipathic alpha-helical structure, LL-37 is strongly electrostatically attracted to the anionic (negatively charged) lipid bilayers of bacteria, fungi, and some enveloped viruses. It inserts itself into the membrane, forming pores that cause essential cellular contents to leak out, leading to rapid pathogen death.

  • Chemotaxis and Immunomodulation: Acts as a highly effective signaling molecule by binding to specific G-protein coupled receptors (such as FPRL1) on immune cells. This triggers the direct migration (chemotaxis) of neutrophils, monocytes, and T-cells to the site of infection or injury to fortify the local immune response.

  • Biofilm Disruption: Modulates and degrades the extracellular polymeric substance (EPS) matrix that protects stubborn bacterial colonies. This effectively penetrates and neutralizes established, drug-resistant biofilms (such as Pseudomonas aeruginosa or Staphylococcus aureus).

Primary Research Applications

LL-37 is a vital compound for in vitro and animal model studies focusing on:

  • Multi-drug resistant (MDR) bacterial and fungal infections

  • Biofilm eradication and prevention mechanisms

  • Cutaneous wound healing, angiogenesis, and re-epithelialization pathways

  • Innate immune system signaling and localized pro/anti-inflammatory modulation

Storage & Handling

For optimal stability and structural integrity, store the lyophilized powder at -4°F (-20°C). Once reconstituted, store at 36°F to 46°F (2°C to 8°C), sealed tightly, and strictly protect from moisture and light.

⚠️ Important Disclaimer for Carbon Nova Labs Customers: All information provided is for educational and reference purposes only. LL-37 is sold strictly for laboratory research use only. This compound is not approved by the FDA for human consumption, therapeutic use, or clinical application. Ensure compliance with all institutional safety protocols and consult qualified professionals before conducting research.