LL-37
Also known as: cathelicidin LL-37 · hCAP18 fragment
The only human cathelicidin, released by proteolytic processing of the precursor hCAP18. A central molecule in innate immunity and in antimicrobial peptide research.
Development status: Preclinical — laboratory and animal studies only
Identifiers and molecular characteristics
- CAS number
- Not verified
- Molecular formula
- Not verified
- Molecular mass
- Not verified
- Amino-acid sequence
- Not verified
- PubChem CID
- Not verified
Identifiers are published only with a source and a check date. Fields marked “not verified” have not yet been confirmed against a primary source — we show the gap rather than an unchecked figure. Always confirm against the certificate of analysis for the specific lot you hold.
Biological targets
- Bacterial membranes
- Formyl peptide receptor-like 1 (immunomodulatory effects)
Mechanism of action
An amphipathic helical peptide that disrupts bacterial membranes through charge and hydrophobicity rather than a specific receptor — a mechanism that makes classical resistance development harder. It also has receptor-mediated immunomodulatory roles distinct from direct killing.
Research evidence and its limits
Extensive molecular and immunological literature. Translating antimicrobial peptides into medicines has proved difficult, largely because of stability and selectivity.
Safety considerations
No regulatory authority has assessed this compound as safe or effective for any human indication. The published record is predominantly laboratory and animal work, which does not establish human safety. Supplied and discussed here strictly as a laboratory research material. Not a medicine, not for human or veterinary administration, and nothing on this page should be read as a dosing, treatment or safety recommendation.
Analytical identification and quality testing
Identity by high-resolution mass spectrometry against the expected mass, purity by RP-HPLC with UV detection. Tandem MS sequencing or peptide mapping gives stronger identity evidence than mass alone.
Regulatory status
Not an approved medicine.
Frequently asked questions
Why have antimicrobial peptides not become common antibiotics?
Stability in vivo, manufacturing cost, and selectivity between bacterial and host membranes. The mechanism that makes them attractive — physical membrane disruption — is also the one hardest to target precisely.
References
Related compounds
Entry last reviewed 2026-10-11. Regulatory status and scientific understanding change; verify against primary sources before relying on anything here.