LL-37

LL-37 in Canada is supplied by Horizon Peptides as a lyophilized powder in sealed 5 mg research vials, available singly or in 3-vial and 10-vial packs. LL-37 is a 37-residue human cathelicidin peptide studied in antimicrobial and immune-signalling research.

LL-37 is the only human cathelicidin, released from a precursor protein called hCAP18. Its name comes from its length and its first two residues: 37 amino acids beginning with two leucines. At 4493.0 it is one of the heaviest sequences stocked.

Unlike most peptides in this catalogue it is naturally occurring rather than designed, and it folds into an amphipathic helix, one face carrying charged residues and the other hydrophobic ones. That arrangement is what underlies its described membrane interactions.

Research attention spans two distinct areas: direct interaction with microbial membranes, and separate immune-signalling roles that do not depend on that activity. Keeping those two lines of enquiry apart is a recurring methodological problem in the literature.

Its length also makes it demanding to synthesise to a consistent standard, which is why purity specification matters more here than for the short sequences stocked alongside it.