When evaluating an LL-37 supplier for analytical or preclinical research, verification of sequence integrity, purity, and low endotoxin burdens is essential for obtaining reproducible experimental data. PX1 Research delivers USA-manufactured, analytical-grade LL-37 with lot-specific documentation to support rigorous laboratory workflows.
When evaluating an LL-37 supplier for analytical or preclinical research, verification of sequence integrity, purity, and low endotoxin burdens is essential for obtaining reproducible experimental data. PX1 Research delivers USA-manufactured, analytical-grade LL-37 with lot-specific documentation to support rigorous laboratory workflows.
When sourcing a verified LL-37 supplier, research institutions require analytical transparency, high chemical purity, and strict endotoxin control. PX1 Research supplies USA-manufactured, research-grade LL-37 (human cathelicidin) verified by lot-specific RP-HPLC and mass spectrometry to exceed 98% purity. Each batch includes comprehensive documentation for in vitro, preclinical, and microbial membrane research applications.
As an essential human cathelicidin peptide, LL-37 plays a pivotal role in cellular host defense models, membrane perturbation assays, and wound-environment studies. Securing this peptide from a domestic, highly controlled manufacturing source ensures that primary cellular assays are free from synthesis artifacts, truncated peptide fragments, or heavy bacterial endotoxin contamination. Laboratories can explore our complete catalog of high-purity research compounds to support complex immunological and antimicrobial assay frameworks.
LL-37 is the sole amphipathic alpha-helical peptide belonging to the cathelicidin family identified in humans. Cleaved proteolytically from the C-terminal region of the hCAP18 pro-protein (human cationic antimicrobial protein 18), LL-37 consists of 37 amino acid residues, beginning with two leucine residues at its N-terminus. Its primary sequence—LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES—imparts a net positive charge (+6 at physiological pH) paired with a distinct hydrophobic domain.
In solution, LL-37 transitions between an unstructured random coil and a highly ordered alpha-helix depending on environmental variables such as peptide concentration, ionic strength, pH, and the presence of lipid membranes. This structural plasticity allows LL-37 to interact dynamically with anionic lipid bilayers. Research detailing these conformational changes can be reviewed within the PX1 Research knowledge base, which aggregates peer-reviewed mechanistic literature for structural biologists and biochemists.
Preclinical studies suggest that LL-37 exerts its primary antimicrobial action through direct, non-receptor-mediated membrane destabilization. Due to its polycationic nature, the peptide preferentially binds to electrostatically negative lipid headgroups—such as phosphatidylglycerol and cardiolipin—commonly found in bacterial cytoplasmic membranes, rather than zwitterionic lipids characteristic of mammalian eukaryotic membranes.
Upon initial electrostatic attraction, LL-37 aligns parallel to the membrane surface before reaching a critical threshold concentration. Once this concentration is attained, the peptide inserts perpendicularly into the lipid bilayer. Biomechanical assays demonstrate that LL-37 disrupts membrane integrity through either a 'carpet-like' detergent mechanism or toroidal pore formation. In vitro models reveal that this membrane disruption leads to rapid dissipation of the transmembrane electrical potential, leakage of essential intracellular metabolites, and subsequent lysis of both Gram-positive and Gram-negative bacterial targets.
Beyond its direct bactericidal activity against planktonic microbes, LL-37 has drawn significant scientific interest for its ability to modulate biofilm architecture. Biofilms represent recalcitrant, extracellular polymeric substance (EPS) matrices that shelter bacterial communities from chemical stressors. In vitro data indicate that sub-inhibitory concentrations of LL-37 interfere with biofilm establishment and promote the dissolution of pre-existing mature biofilms.
Mechanistic investigations using fluorescence microscopy and gene expression profiling indicate that LL-37 downregulates key genes involved in quorum sensing and flagellar assembly, such as the *rhl* and *las* systems in *Pseudomonas aeruginosa*. Additionally, the peptide stimulates surface motility (twitching), which prevents bacteria from settling into stable microcolonies. Researchers evaluating anti-biofilm agents can source verified LL-37 peptide vials directly from PX1 Research to maintain baseline accuracy in EPS matrix disruption assays.
In addition to direct microbial membrane interactions, LL-37 functions as an immunomodulatory signaling peptide within localized cell matrices. Preclinical models demonstrate that LL-37 binds to specific host cell receptors—including formyl peptide receptor 2 (FPR2/ALX), purinergic P2X7 receptors, and epidermal growth factor receptors (EGFR)—to recruit immune effector cells and stimulate tissue remodeling cascades.
In wound-environment research models, in vitro assays show that LL-37 induces the migration of neutrophils, monocytes, and T-lymphocytes to site-specific signaling gradients. Furthermore, the peptide promotes re-epithelialization by stimulating human keratinocyte migration and proliferation without triggering aberrant apoptosis. Preclinical literature also highlights the peptide's capacity to bind bacterial lipopolysaccharide (LPS), neutralizing endotoxin-mediated TLR4 signaling and dampening excessive, systemic pro-inflammatory cytokine secretion.
When designing comparative immunology or tissue-repair experiments, investigators often evaluate LL-37 alongside other regulatory peptides. While LL-37 exhibits dual antimicrobial and receptor-mediated signaling functions via an alpha-helical amphipathic domain, compounds like Thymosin Alpha-1 primarily modulate T-cell activation and adaptive immune pathways without directly disrupting bacterial membranes. Similarly, KPV, a C-terminal tripeptide fragment of alpha-MSH, operates via nuclear factor-kappa B (NF-κB) down-regulation to suppress localized mucosal inflammation.
For tissue regeneration and cell-migration models, researchers frequently compare cathelicidin responses against signaling motifs found in BPC-157, which acts through VEGFR2 expression and focal adhesion kinase pathways rather than direct cationic membrane action. Understanding these operational differences allows research teams to select the precise molecular tool required for their specific in vitro model system. Additional context regarding these pathways is available in our analysis of innate immunity research peptides.
Because LL-37 contains 37 amino acids with multiple hydrophobic residues, solid-phase peptide synthesis (SPPS) of this sequence is technically demanding. Truncated species, deletion sequences, and enantiomeric impurities can significantly skew receptor binding affinities and membrane insertion kinetics. Consequently, strict analytical verification is mandatory for every production lot.
PX1 Research subjects every lot of LL-37 to rigorous quality control protocols within ISO 17025 accredited laboratory environments. Purity is validated using Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC), ensuring a purity profile exceeding 98%. Molecular mass and sequence identity are confirmed via Electrospray Ionization Mass Spectrometry (ESI-MS). Furthermore, given LL-37's interaction with LPS models, every lot undergoes chromogenic Limulus Amebocyte Lysate (LAL) testing to confirm ultra-low endotoxin levels (<0.01 EU/mg), ensuring reliable assay performance.
Maintaining chemical stability and preventing non-specific peptide loss are critical considerations when working with purified LL-37 in laboratory environments. Lyophilized LL-37 should be stored at -20°C or -80°C in a desiccated environment away from light, where it remains stable for up to 24 months. Repeated freeze-thaw cycles must be strictly avoided to prevent peptide aggregation and backbone cleavage.
For reconstitution, research teams should adhere to standardized peptide reconstitution and handling protocols. Lyophilized LL-37 should first be brought to room temperature in a desiccator to minimize condensation. Reconstitution in sterile, non-pyrogenic bacteriostatic water or sterile phosphate-buffered saline (PBS, pH 7.4) is recommended. Due to its hydrophobic interactions, LL-37 may adhere to glass or standard polypropylene tube walls; therefore, using low-binding microcentrifuge tubes or adding a low concentration of carrier protein (such as 0.1% BSA) for ultra-dilute working solutions is advised.
PX1 Research operates dedicated, GMP-compliant manufacturing facilities within the United States, providing complete supply chain transparency and lot traceability from raw amino acid coupling to final lyophilization. By maintaining domestic synthesis and state-of-the-art analytical facilities, we mitigate the quality risks, delays, and degradation hazards associated with overseas re-packaging operations.
Orders are dispatched via expedited cold-chain shipping directly from our primary distribution hubs in California and Arizona. Orders placed Monday through Friday receive same-day fulfillment, ensuring that heat-sensitive lyophilisates arrive at university, biotechnology, and corporate research laboratories with uncompromised biological activity. Principal investigators managing large-scale screening campaigns can apply for our institutional wholesale purchasing program to lock in batch-consistent supply lines.
What is the primary scientific application of LL-37 in laboratory settings?
LL-37 is primarily utilized in laboratory research to study innate immune responses, antimicrobial membrane disruption mechanisms, bacterial biofilm breakdown, LPS-neutralization signaling, and cell-migration kinetics in wound-healing tissue models.
How does PX1 Research verify the purity of its LL-37 peptide lots?
PX1 Research verifies every lot of LL-37 using Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) for purity quantification and Electrospray Ionization Mass Spectrometry (ESI-MS) for exact molecular weight confirmation. A lot-specific Certificate of Analysis (COA) is provided with each shipment.
What endotoxin levels are expected in PX1 Research LL-37 preparations?
Every batch of LL-37 undergoes LAL (Limulus Amebocyte Lysate) testing to ensure endotoxin levels remain below 0.01 EU/mg, preventing non-specific inflammatory background noise in sensitive cell culture and immunological assays.
What is the recommended storage temperature for lyophilized LL-37?
Lyophilized LL-37 should be stored at -20°C or -80°C in a dry, dark environment. Once reconstituted, liquid aliquots should be kept at -80°C to prevent degradation, avoiding repeated freeze-thaw cycles.
How should LL-37 be reconstituted to prevent container surface adsorption?
LL-37 should be reconstituted using sterile laboratory-grade water or buffered saline solutions in low-binding polypropylene tubes. For highly dilute working concentrations, adding a 0.1% bovine serum albumin (BSA) or human serum albumin (HSA) carrier can prevent non-specific adsorption to tube walls.
Can LL-37 be used for human administration or therapeutic clinical use?
No. LL-37 supplied by PX1 Research is strictly synthesized for laboratory, in vitro, and preclinical research applications. It is not intended for human or animal clinical use, therapeutic administration, or diagnostic procedures.
Where does PX1 Research manufacture and ship its LL-37 compound?
PX1 Research synthesizes all peptides in GMP-compliant, USA-based facilities. Orders are fulfilled and shipped same-day (Monday through Friday) from our fulfillment centers located in California and Arizona.
What receptor pathways are associated with LL-37 in cell culture studies?
In cell culture studies, LL-37 has been shown to interact with formyl peptide receptor 2 (FPR2/ALX), purinergic P2X7 receptors, and epidermal growth factor receptors (EGFR), initiating localized intracellular kinase cascades.
All products are sold strictly for laboratory and research use only. Not for human or veterinary use, diagnosis, treatment or consumption. Statements have not been evaluated by the FDA.