LL37

LL-37 is the only human cathelicidin: a 37-amino-acid, positively charged peptide that folds into an α-helix. It is cut from a larger precursor protein (hCAP18), and its name comes from its first two amino acids (two leucines) and its length. It is one of the most studied antimicrobial peptides of the innate immune system.

Published research on LL-37 spans cell culture, animal models and human tissue studies of the innate immune system. It has been examined in vitro for antimicrobial activity against bacteria, fungi and viruses, including interactions with microbial membranes and biofilms, and for immune-signaling roles such as attracting immune cells through the FPR2 receptor. Its natural expression has been studied in skin conditions such as psoriasis and rosacea, and it has been investigated in a clinical trial in people with venous leg ulcers. Findings in cells or animals do not establish effects in people.

No. LL-37 is not approved by the FDA or any other regulator as a medicine; it has been tested only in early-stage clinical research. It is a naturally occurring human peptide, but that does not make any product containing it an approved drug. The material sold here is a research reagent for laboratory use only.

LL-37 is a positively charged, amphipathic peptide that generally dissolves in sterile water. Let the sealed vial reach room temperature, add the diluent slowly down the inside wall and swirl gently without shaking. Because LL-37 can self-associate in salt-containing buffers and stick to some plastic surfaces, labs often prepare stock solutions in water and use low-binding tubes. Keep the solution refrigerated and avoid repeated freeze-thaw cycles.

LL-37 is a 37-amino-acid cathelicidin, cut from the hCAP18 protein and studied as an antimicrobial peptide of the innate immune system. KPV is a three-amino-acid fragment of α-MSH studied in inflammation models. They differ in size (about 4.5 kDa versus 342 Da), origin and research area, and share no sequence.

Both are studied in immunology but are unrelated. Thymosin alpha-1 is a 28-amino-acid acetylated peptide from prothymosin alpha, researched for its role in T-cell maturation and Toll-like receptor signaling. LL-37 is a 37-amino-acid cathelicidin, cut from the hCAP18 protein, researched mainly as an antimicrobial peptide of the innate immune system. They share no sequence.

LL37: molecular formula C205H340N60O53; molecular weight 4493.3 g/mol; CAS number 154947-66-7. Sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES. Match these identifiers against the Certificate of Analysis for the lot.

Yes. Each lot has its own Certificate of Analysis, linked on this page for the current lot of each size: 5mg (99.6% HPLC purity). Past certificates are archived in the COA library; contact us with the lot number on the vial label if a certificate is missing.

99.6% (HPLC, current lot). Purity is measured by high-performance liquid chromatography (HPLC) and reported on the lot's Certificate of Analysis.

LL37 is supplied as lyophilized powder in a sealed vial: 5mg. In stock and dispatched in 1–2 business days. Quantity pricing applies automatically at 5+ and 10+ vials of the same size.

Store sealed at −20 °C, dry and protected from light.