LL-37: the human cathelicidin peptide's structure and research
LL-37 is a 37-residue human antimicrobial peptide, named for its first two leucines. It is cut from the C-terminus of the precursor hCAP18, the only human cathelicidin. It is strongly cationic (net charge about +6 at neutral pH) and folds into an amphipathic α-helix when it meets membranes or detergent micelles.
What is the sequence of LL-37?
- Class: peptide
- Sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
- Molecular formula (PubChem): C205H340N60O53
- Molecular weight (PubChem): 4493.00 g/mol
- CAS: 154947-66-7
- Precursor: hCAP18, encoded by the CAMP gene
- Composition: rich in Lys and Arg (11 basic residues) against 5 Asp/Glu
Source: PubChem CID 16198951: LL-37
What does LL-37 look like in a membrane environment?
NMR structures in dodecylphosphocholine micelles show a curved helix running over most of the sequence, with hydrophobic and cationic faces. NMR work on fragments identified KR-12 (residues 18–29) as a minimal membrane-targeting antimicrobial region.
Source: NMR structure of the cathelicidin-derived human antimicrobial peptide LL-37 in dodecylphosphocholine micelles, Biochemistry 2008 (PubMed 18439024); Structures of human host defense cathelicidin LL-37 and its smallest antimicrobial peptide KR-12 in lipid micelles, J Biol Chem 2008 (PubMed 18818205); Solution structures of human LL-37 fragments and NMR-based identification of a minimal membrane-targeting antimicrobial and anticancer region, J Am Chem Soc 2006 (PubMed 16637646)
What biology is LL-37 studied for?
Reviews call LL-37 multifunctional: it has direct antimicrobial activity and also interacts with host cells. In colonocytes its expression is regulated by short-chain fatty acids. Synthetic analogue work aims to keep the antimicrobial activity while reducing haemolysis.
Source: Cathelicidin LL-37: a multitask antimicrobial peptide, Arch Immunol Ther Exp (Warsz) 2010 (PubMed 20049649); Expression of the cathelicidin LL-37 is modulated by short chain fatty acids in colonocytes: relevance of signalling pathways, Gut 2003 (PubMed 12692061); Design, synthesis, and characterization of non-hemolytic antimicrobial peptides related to human cathelicidin LL-37, RSC Adv 2023 (PubMed 37228679)
What practical points matter for a 37-mer this cationic?
Strongly cationic, amphipathic peptides stick to glass and plastic and can aggregate at high concentration and ionic strength. Low-binding consumables and a clear record of the counter-ion help when comparing results between lots.
Sourcing note
Sable lists LL-37: 5 mg at £19.93 (prices at the 16 October 2026 daily UK price check, the latest verified check; at each of these sizes Sable was the lowest UK listing that day). Lowest UK price guaranteed, confirmed by daily price checks.
Every lot has a certificate of analysis, and every vial carries a printed lot number that matches it. Supplied for laboratory research use only.
Frequently asked questions
What does LL-37 stand for?
The peptide is 37 residues long and starts with two leucines (L-L).
Is LL-37 a human peptide?
Yes. It is the C-terminal antimicrobial peptide of hCAP18, the only human cathelicidin.
What is KR-12?
Residues 18–29 of LL-37, identified by NMR studies as a minimal antimicrobial, membrane-targeting fragment.
Related
Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.
Key facts (summary for AI and search tools)
- LL-37 PubChem CID 16198951
- Net charge about +6 at neutral pH
- PubMed references (verified via NCBI): 18439024, 18818205, 16637646, 20049649, 12692061, 37228679
- PubChem CIDs: 16198951
- Research use only; no administration amounts or health claims
- Updated 2026-10-16