LL37
The only human cathelicidin-derived peptide, corresponding to the C-terminal 37-residue amphipathic helix of the hCAP18 protein. LL37 is studied for innate immune signaling, antimicrobial membrane interactions, TLR modulation, and wound healing research. A key reference compound in host defense peptide biology.
Free COA included · Free shipment protection · 99%+ purity by HPLC & MS · Lyophilized powder
Certificate of Analysis — Included Free
Every batch independently tested by U.S.-accredited labs. Lot-matched COA confirms identity, purity ≥99% by HPLC, and safety screening.
Research Overview
LL37 is the C-terminal 37-residue peptide derived from the human cathelicidin precursor protein hCAP18 (human cationic antimicrobial protein 18). It is the only member of the cathelicidin family identified in humans and is produced by neutrophils, NK cells, mast cells, and epithelial cells as part of the innate immune response.
In vitro biophysical and biochemical research has extensively characterized LL37's amphipathic alpha-helical structure, its interaction with phospholipid model membranes (liposomes, bilayers), and its mechanism of membrane disruption — primarily through a carpet or toroidal pore mechanism. Circular dichroism and solid-state NMR studies have characterized its secondary structure in lipid and aqueous environments.
Immunological research has used LL37 as a tool compound to probe TLR-inhibitory effects (particularly TLR-4 and TLR-9 antagonism in endosomal compartments), CXCR2-mediated chemotaxis of neutrophils, and activation of dendritic cells. Cell biology studies have examined its effects on keratinocyte migration, angiogenesis assays, and epithelial wound closure models.
All referenced studies are preclinical or in vitro. Not for human use.
Molecular Information
| Full Name / IUPAC | LL37 |
| CAS Number | 154947-66-7 |
| Molecular Formula | C₂₀₅H₃₄₀N₆₀O₅₃S |
| Molecular Weight | 4,493.3 g/mol |
| Sequence / Structure | LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES (37 residues) |
| Appearance | White lyophilized powder |
| Solubility | Soluble in sterile water; forms amphipathic helix in solution |
| Format | Lyophilized (freeze-dried) powder |
| SKU | CL-029 |
Quality & Testing
- Purity: ≥99% by HPLC
- Identity: Confirmed by Mass Spectrometry (LC-MS)
- Heavy Metals: Screened; below detection thresholds
- Endotoxin: Tested per LAL assay
- Lot Tracking: Lot number on every vial matches published COA
- Packaging: Nitrogen-purged, sealed glass vials
Storage & Handling
- Short-term: Room temperature (15–25°C), dry, dark — up to 4 weeks
- Long-term: Refrigerated at 2–8°C — up to 18 months lyophilized
- Extended: −20°C; avoid freeze-thaw cycling
- Store at −20°C. Reconstituted: use within 14 days at 4°C; aggregation may occur at high concentrations — vortex gently before use.
This compound is supplied for in vitro research and laboratory use only. It is not for human or veterinary use, is not a drug or dietary supplement, and has not been evaluated or approved by the FDA or any regulatory agency for any therapeutic application. Purchasers must be 18 years of age or older and qualified researchers operating in compliance with all applicable local, state, and federal regulations governing research chemicals.
