LL-37

PeptideXpo buyer fit

Overview

LL-37 is the only human cathelicidin and the C-terminal 37-amino-acid antimicrobial peptide released by proteolytic cleavage of the hCAP-18 precursor protein. The sequence (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) is highly cationic with an amphipathic α-helical fold in membrane-mimetic environments, properties that drive direct membrane disruption against a broad spectrum of Gram-positive and Gram-negative bacteria, fungi, and enveloped viruses. Beyond direct antimicrobial activity, LL-37 modulates innate immune signaling through formyl-peptide receptor 2 (FPR2) and is studied for its roles in wound-healing chemotaxis, autoimmunity, and inflammatory disease research. PeptideXpo supplies LL-37 as a lyophilized powder at ≥99.0% HPLC purity. The 37-residue cationic sequence presents distinctive analytical and handling challenges: the molecule adsorbs strongly to standard polypropylene and glass surfaces at low working concentrations (the cationic charge density drives surface binding), which can produce 30-70% concentration loss between the nominal weight-out and the effective in-assay concentration if low-bind plasticware is not used. Working dilutions for cell-culture and assay work should be prepared in low-bind tubes with 0.1% acid-free BSA or 0.01% Tween-20 carrier to suppress surface adsorption. Endotoxin (LAL) and microbial limits are essential add-ons for any in vivo or cell-based assay work because LL-37's innate-immune signaling activity overlaps with the pathways activated by bacterial endotoxin.

Who buys this, and why

Buyers in this category are research labs studying immune-modulation, cytokine signaling, and antimicrobial activity. The defining QC requirement is bacterial-endotoxin control: many of the downstream assays (NF-κB reporters, macrophage activation panels, neutrophil-priming readouts) are themselves activated by endotoxin contamination, so a clean LAL on the specific batch is a precondition rather than a nice-to-have. LL-37 and related cationic antimicrobial peptides additionally benefit from low-bind plasticware during dilution.

Primary buyer fit: academic and contract research laboratories.

Specifications

CAS

154947-66-7

Appearance

White to off-white lyophilized powder

Purity (HPLC)

≥ 99.0%

Strength

5 mg

Packaging

10 vials/box · base pack (multiples of 10)

Half-life

≈ 90-120 minutes

MOQ

On request

Lead time

14–21 days

Storage

-20°C, protect from light

Documentation available on request

• Certificate of Analysis (COA)
• HPLC Chromatogram
• Mass-spec identity (ESI-MS)
• Bacterial endotoxin (LAL, USP <85>)
• Microbial limits (USP <61>/<62>)
• Bioburden screening
• Sequence verification (LC-MS/MS)
• SDS / MSDS

Regulatory note

Sold for research use only under the receiving laboratory's local regulations. Not a finished dosage form. For in vivo or cell-based assay workflows, request bacterial-endotoxin testing on the specific batch at quote stage so the COA carries the LAL value.

Selected literature

1. Agerberth B, Gunne H, Odeberg J, Kogner P, Boman HG, Gudmundsson GH. FALL-39, a putative human peptide antibiotic, is cysteine-free and expressed in bone marrow and testis. Proc Natl Acad Sci U S A. 1995;92(1):195-199.
2. Dürr UHN, Sudheendra US, Ramamoorthy A. LL-37, the only human member of the cathelicidin family of antimicrobial peptides. Biochim Biophys Acta. 2006;1758(9):1408-1425.
3. Bals R, Wang X, Zasloff M, Wilson JM. The peptide antibiotic LL-37/hCAP-18 is expressed in epithelia of the human lung where it has broad antimicrobial activity at the airway surface. Proc Natl Acad Sci U S A. 1998;95(16):9541-9546.
4. Koczulla R, von Degenfeld G, Kupatt C, et al. An angiogenic role for the human peptide antibiotic LL-37/hCAP-18. J Clin Invest. 2003;111(11):1665-1672.
5. Yang B, Good D, Mosaiab T, et al. Significance of LL-37 on immunomodulation and disease outcome. Biomed Res Int. 2020;2020:8349712.
6. Ohuchi K, Ikawa T, Amagai R, et al. LL-37 might promote local invasion of melanoma by activating melanoma cells and tumor-associated macrophages. Cancers (Basel). 2023;15(6):1678.

Frequently asked questions