LL-37 is the only known human cathelicidin-derived antimicrobial peptide, a 37-residue cationic, amphipathic sequence released from the precursor protein hCAP18. Studied both as a direct antimicrobial agent and as a multifaceted immunomodulatory and tissue-repair molecule, it is a central tool for host-defense and wound-healing research. Puritide Research supplies LL-37 as a high-purity, research-use-only material, synthesized for in vitro and animal-model work and backed by third-party-verified certificates of analysis.
Product Specifications
- Application
- Antimicrobial host-defense and immunomodulation research (human cathelicidin)
- Appearance
- Solid, white lyophilized powder in a sealed glass vial
- Chemical Formula
- C205H340N60O53
- PubChem SID
- 16198951
- CAS Number
- 154947-66-7
- Molecular Weight
- ~4493.33 g/mol
- Synonyms
- LL-37, Cathelicidin LL-37, hCAP18 (134-170), CAP-18, human cathelicidin antimicrobial peptide
- Storage
- Store at ≤25°C, sealed, away from heat, light, and moisture. For extended storage, keep lyophilized and refrigerated or frozen.
What Is LL-37?
LL-37 is the mature antimicrobial peptide cleaved from the C-terminal domain of human cathelicidin antimicrobial protein 18 (hCAP18). Its name reflects its two leading leucine residues and its length of 37 amino acids. In humans it is the sole cathelicidin family member and a key effector of innate immunity.
The peptide is cationic, amphipathic, and adopts an alpha-helical conformation in membrane-like environments, properties central to its interaction with microbial membranes. Beyond direct antimicrobial activity, LL-37 is studied as an immunomodulator that influences inflammatory signaling, chemotaxis, angiogenesis, and epithelial repair.
Present understanding derives from in vitro assays and animal models. Findings should be interpreted within their experimental context and not treated as established clinical outcomes. Puritide Research supplies LL-37 strictly for laboratory use; it is not approved for human or veterinary application.
LL-37 Mechanism of Action (Research Only)
LL-37 is studied for a dual profile: direct disruption of microbial membranes and broad modulation of host immune signaling. The observations below reflect biochemical assays, cell-culture studies, and animal models, and should be read strictly in a research context.
Membrane Interaction and Antimicrobial Activity
As a cationic, amphipathic alpha-helical peptide, LL-37 is studied for its interaction with negatively charged microbial membranes. Models describe insertion and destabilization of the lipid bilayer leading to loss of membrane integrity, activity reported against Gram-negative and Gram-positive bacteria as well as certain viral and fungal targets in vitro.
Immunomodulation and Tissue Repair
Beyond membrane activity, LL-37 is investigated as an immunomodulatory molecule that influences chemotaxis of immune cells, cytokine signaling, and the balance of pro- and anti-inflammatory responses. It has been studied for interactions with formyl peptide receptors and for modulation of Toll-like receptor signaling.
In wound-healing models LL-37 is associated with re-epithelialization, angiogenesis, and granulation-tissue formation. Researchers use it to study the intersection of antimicrobial defense and tissue repair under defined conditions rather than to establish physiological effects.
LL-37 Research Applications
LL-37 is investigated across immunology, microbiology, and preclinical wound-healing studies. The observations below derive from biochemical studies, cell-based assays, and animal models, and should be interpreted within their respective settings.
Antimicrobial and Host-Defense Models
A primary application is investigating antimicrobial activity against a range of pathogens in vitro, including studies of membrane disruption, biofilm interference, and structure-activity relationships across LL-37 fragments and analogs.
LL-37 is also studied in host-defense models examining how the peptide contributes to innate immunity and interacts with microbial and host membranes under controlled conditions.
Immunomodulation and Wound-Healing Studies
Researchers use LL-37 to study immune-cell chemotaxis, cytokine modulation, and inflammatory signaling, as well as wound-repair endpoints such as re-epithelialization and angiogenesis in cell and animal models. These studies aim to characterize the peptide's dual antimicrobial and immunomodulatory roles rather than to establish therapeutic outcomes.
Laboratory Safety & Handling (Research Use Only)
LL-37 is a synthetic, lyophilized research peptide for laboratory investigation only. It should be handled by qualified personnel in controlled environments, in accordance with institutional policies, laboratory safety procedures, and applicable regulations. As an investigational material, laboratories should implement practices that prioritize material integrity, traceability, and reproducibility.
Handling & Storage Guidelines
Follow institutional SOPs, chemical hygiene plans, and approved protocols; wear appropriate PPE (lab coat, gloves, eye protection); and use engineering controls where required. Record lot numbers, storage conditions, and handling activities, and retain Certificates of Analysis and batch documentation to support traceability and audit readiness.
Store material under the conditions specified in product documentation, protected from excessive heat, moisture, and direct light. Maintain consistent conditions throughout the study period and monitor storage records as part of quality assurance. Consistent handling and documentation support reliable, reproducible outcomes.
Certificate of Analysis & Quality Assurance
Each LL-37 batch ships with a third-party-verified Certificate of Analysis, providing transparent, research-grade quality control. The CoA includes a purity assessment (HPLC / reverse-phase chromatography), mass-spectrometry identity confirmation, and lot number, testing date, and method documentation.
Researchers may request sample CoAs (PDF) ahead of purchase to confirm testing parameters, analytical methods, and batch consistency, and are encouraged to perform independent verification.
Research Use Only
