Buy LL-37 10mg Online

LL-37 is the only cathelicidin-derived antimicrobial peptide found in humans, a 37-residue sequence beginning with two leucines — hence the name — released by proteolytic cleavage from the precursor protein hCAP18 in neutrophils and epithelial cells. Its molecular weight is 4493 Da and its sequence is LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES. The peptide is cationic and amphipathic: it folds into a helix with charged residues along one face and hydrophobic residues along the other, and that arrangement lets it bind the negatively charged surface of bacterial membranes and insert into the lipid bilayer. Structural work published in Scientific Reports shows it oligomerises and forms channels in membrane mimics. Because mammalian cell membranes carry cholesterol and a largely neutral outer leaflet, the selectivity for microbial membranes follows from surface charge rather than from a receptor. Beyond direct antimicrobial action LL-37 functions as a host-defence peptide, affecting chemotaxis, wound healing and epithelial cell migration, and it can present nucleic acids to scavenger receptors — a route by which it also amplifies inflammatory signalling.