Host-defence and tissue-repair peptides
LL-37
LL-37 is the 37-residue C-terminal fragment of the human cathelicidin hCAP18 and the only cathelicidin-derived peptide in humans; it forms an amphipathic α-helix.
- TypePeptide
- FormulaC205H340N60O53
- Average mass4493.26 g/mol
- CAS154947-66-7
- Vesta listings1
Reference page for laboratory use · updated 2026-10-30
Overview
LL-37 at a glance
The sequence is LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES. The literature covers its antimicrobial activity, supramolecular structure (including a published structure of the LL-37(17-29) fragment) and its binding to plasma proteins.
It is a standard reference peptide in antimicrobial peptide and host-defence research.
Structure
LL-37 is rich in lysine and arginine, which gives it a strong positive charge at neutral pH. The calculated formula from the sequence matches PubChem exactly.
Identity
Identity data
| Name | LL-37 |
|---|---|
| Also written as | Cathelicidin LL-37, hCAP18(134-170) |
| Type | Peptide |
| Research area | Host-defence and tissue-repair peptides |
| Molecular formula | C205H340N60O53 |
| Monoisotopic mass | 4490.5754 Da |
| Average molecular weight | 4493.26 g/mol |
| CAS number | 154947-66-7 |
| Sequence | LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES |
| PubChem record | CID 16198951 |
The formula was calculated independently from the written sequence and matches the PubChem record exactly. Reference data retrieved on 2026-10-30. Compare these values with the batch certificate of analysis, using the compound identity file template.
Expected values
Mass spectrometry reference
Ions calculated from the monoisotopic mass 4490.5754 Da. Use them to check an LC-MS result; for larger peptides the instrument usually reports a deconvoluted mass close to 4493.3 Da instead.
| Ion | m/z |
|---|---|
| [M+3H]3+ | 1497.8657 |
| [M+4H]4+ | 1123.6511 |
| [M+5H]5+ | 899.1224 |
| [M+6H]6+ | 749.4365 |
For molecules of this size the tallest isotope peak is one to two mass units above the monoisotopic peak. Read the guide to average and monoisotopic mass for how these values are calculated.
Quality
Analytical notes for batch documents
- Highly charged peptides give high charge states in electrospray MS; the deconvoluted mass should be about 4493 Da.
- Cationic amphipathic peptides adsorb to plastic and glass; low-bind labware is recommended in the laboratory.
- Mass shifts to look for in this sequence: deamidation of Asn or Gln (+0.984 Da).
- The molecular weight of a vial of powder includes counter-ions and water; the share of the powder that is peptide is the net peptide content.
Terms used on this page: Peptide.
Vesta listings
LL-37 formats and prices
| Product | Per vial | SKU | Price per kit | Price per vial |
|---|---|---|---|---|
| LL37 | 5 mg | LL37 | $138.06 | $13.81 |
Prices are per kit of 10 vials in US dollars. Shipping is paid by the customer and is shown in the cart. Volume savings of 5 %, 8 % and 10 % apply from $350.00, $600.00 and $1,000.00. See the full price list.
Published literature
Selected scientific literature
Bibliographic details were read from PubMed on 2026-10-30. The papers are listed for scientific reference; Vesta makes no claim about the use of its research materials in people or animals.
- The Human LL-37(17-29) antimicrobial peptide reveals a functional supramolecular structureEngelberg Y, Landau M · Nat Commun · 2020 · PMID 32753597
- The antimicrobial peptide LL-37 binds to the human plasma protein apolipoprotein A-IWang Y, Johansson J, Agerberth B et al. · Rapid Commun Mass Spectrom · 2004 · PMID 14978805
Questions
Frequently asked questions
What is LL-37?
LL-37 is the 37-residue C-terminal fragment of the human cathelicidin hCAP18 and the only cathelicidin-derived peptide in humans; it forms an amphipathic α-helix.
What is the molecular weight of LL-37?
LL-37 has the formula C205H340N60O53, an average molecular weight of 4493.26 g/mol and a monoisotopic mass of 4490.5754 Da. A salt form, a different counter-ion or a metal complex changes the molecular weight printed on a certificate of analysis, so compare like with like.
How can I check the identity of a batch of LL-37?
Compare the intact mass measured by LC-MS with the expected values on this page, for example [M+4H]4+ at m/z 1123.6511. Confirm that one main HPLC peak carries that mass and that the batch code on the report matches the vial. The guides on mass spectrometry and on certificates of analysis explain each step.
Which LL-37 products does Vesta list?
Vesta lists 1 product for LL-37: 5 mg per vial in kits of 10 vials. Prices are shown per kit in US dollars, and shipping is paid by the customer.