LL37

LL-37 is a 37-residue peptide released from the human cathelicidin precursor, with a sequence beginning with two leucines.

Identity

Sequence

H-LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES-OH

Residues

37

Molecular formula

C₂₀₅H₃₄₀N₆₀O₅₃

Average molecular weight

4493 g/mol

Monoisotopic mass (calculated)

4490.5754 Da

CAS number

154947-66-7

PubChem CID

16198951

UniProt P49913 identifies the precursor; LL-37 is its 134–170 fragment. The stated weight belongs to the free fragment, not the precursor. An intact SMILES representation was not verified.

Identity data from: PubChem CID 16198951 · UniProtKB P49913

Research overview

LL-37 is the 37-residue C-terminal peptide of the human cathelicidin precursor hCAP18. Its name combines the two initial leucine residues with the length of the processed chain. Structural research examined purified LL-37 using crystallography, biochemical measurements and electron microscopy. The investigators described pairs of antiparallel helices with amphipathic surfaces, followed by structural changes in the presence of detergents. Assemblies observed in crystals were also examined in lipid-vesicle systems, connecting the peptide’s organization with the membrane environment. These observations concern defined peptide–lipid and peptide–detergent models rather than a single fixed conformation in every setting [1].

A separate line of research examined cell signaling and directed migration. Experiments with isolated human monocytes and HEK293 cells expressing FPRL1 measured calcium mobilization after exposure to LL-37. The investigators also studied migration of neutrophils and T cells, relating these observations to the formyl-peptide receptor system. This study connects the peptide to a specific receptor-mediated experimental response, while the structural work concerns interactions with membrane components. Combining the two papers therefore outlines distinct aspects of LL-37 research; a membrane assembly and a cell-signaling measurement should remain separate observations [2].

Laboratory storage and handling

Keep the sealed vial cold, dry and protected from light, following the conditions in the documentation supplied with the lot. Let the vial reach room temperature before opening to limit moisture condensation. Avoid repeated freezing and thawing of laboratory stocks. Record the lot identifier and the material form with each experiment, and use standard laboratory protective equipment.

Questions about LL-37

References

1. Structural remodeling and oligomerization of human cathelicidin on membranes suggest fibril-like structures as active species. Sci Rep 2017. PMID 29133814
2. LL-37, the neutrophil granule- and epithelial cell-derived cathelicidin, utilizes formyl peptide receptor-like 1 (FPRL1) as a receptor to chemoattract human peripheral blood neutrophils, monocytes, and T cells. J Exp Med 2000. PMID 11015447

Identity data checked on 2026-10-03. Literature summaries describe published research models and are not specifications of any product lot.