LL-37Also known as: Cathelicidin antimicrobial peptide, hCAP-18, LL37

Mechanism of Action

LL-37 is an amphipathic cationic peptide from the cathelicidin family that disrupts microbial membranes by binding to and permeabilizing their lipid bilayers, leading to pathogen death. It also modulates immune responses by influencing inflammatory signaling pathways, promotes angiogenesis (new blood vessel formation) supporting tissue repair, and can enhance barrier functions of epithelial cells.

Reported Research Benefits

LL-37 is researched for antibacterial and antiviral properties, wound healing acceleration, immunomodulation in autoimmune and chronic inflammatory conditions, and improving skin, lung, and gut barrier health. It is also studied for role in chronic infection resistance.

Dosing Protocol & Reconstitution

Typically supplied as lyophilized powder to be reconstituted with bacteriostatic water. Research dosing varies widely depending on in vitro or in vivo study design; no standardized human clinical dose is established. Storage recommended at 2-8°C after reconstitution, stable up to 60 days.

Research Notes

LL-37 shows promising efficacy in preclinical models for enhancing wound repair, reducing inflammation, and antibacterial activity. It is a focus for research in autoimmune diseases, chronic wounds, and infectious diseases. Its biological half-life in physiological conditions varies and may be subject to proteolytic degradation.

Research Summary

LL-37 is the only known human cathelicidin antimicrobial peptide, derived from hCAP18. It directly disrupts bacterial, fungal, and viral membranes, and also modulates innate immune responses, promotes wound healing, and stimulates angiogenesis. Clinical research is exploring its use in chronic wounds, atopic dermatitis, and respiratory infections.

Side Effects & Safety

Dose-dependent cytotoxicity to mammalian cells at high concentrations. Potential for inflammatory responses and mast cell degranulation. Systemic injection may cause transient pain and local inflammation. High doses linked to hemolysis in vitro; systemic safety at research doses requires careful titration.

Stability & Storage

Refer to research notes

Molecular Data

Sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Molecular Formula: C211H385N63O53S
Molecular Weight: 4493.1 g/mol
CAS Number: 222256-30-4
IUPAC Name: N-((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-((((1S)-1-(((2S)-2-((2S)-2-amino-3-(4-hydroxyphenyl)propanamido)propanamido)butanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)propanamido)

Primary literature: https://pubmed.ncbi.nlm.nih.gov/?term=LL-37+cathelicidin+antimicrobial+peptide