Antimicrobial Research Peptides

11 research peptides demonstrate antimicrobial properties. This collection covers their mechanisms, evidence base, and research applications.

Preclinical | Antimicrobial / Immune

LL-37 is the only human cathelicidin antimicrobial peptide, a 37-amino-acid cationic peptide (sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) with broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi,...

Mechanism: LL-37 (C120H232N42O38) carries a net positive charge (+6) that binds negatively charged bacterial membranes, creating transmembrane pores causing cell lysis. It also has anti-biofilm activity.

Preclinical | Anti-Inflammatory / Immune

KPV is a naturally occurring tripeptide (Lys-Pro-Val, MW ~342.4 g/mol) derived from the C-terminal region (positions 11–13) of alpha-melanocyte-stimulating hormone (α-MSH).

Mechanism: KPV exerts anti-inflammatory effects through a mechanism distinct from the parent α-MSH hormone. Rather than acting through melanocortin receptors (which would trigger pigmentation), KPV is...

Basic Science / Endogenous Reference | Antimicrobial / Immune

Beta-defensins are a family of small cationic antimicrobial peptides (36-45 amino acids, MW ~4-5 kDa) produced by epithelial cells throughout the body.

Mechanism: Beta-defensins are cationic amphipathic peptides containing three conserved disulfide bonds in a characteristic beta-sheet structure.

Basic Science / Endogenous Reference | Antimicrobial / Immune

Alpha-defensins are a family of small cationic antimicrobial peptides (29-35 amino acids, MW ~3.5-4.5 kDa) with three characteristic intramolecular disulfide bonds.

Mechanism: Alpha-defensins are cationic peptides with a triple-stranded beta-sheet structure stabilized by three disulfide bonds (Cys1-Cys6, Cys2-Cys4, Cys3-Cys5 connectivity).

Preclinical Only | Antimicrobial / Immune

Lactoferricin is a 25-amino-acid antimicrobial peptide (f17-41 of bovine lactoferrin; MW ~3126 g/mol for bovine form) generated by pepsin digestion of lactoferrin.

Mechanism: Lactoferricin is a cationic amphipathic peptide derived from the N-terminal region of lactoferrin. The bovine form (LfcinB, residues 17-41: FKCRRWQWRMKKLGAPSITCVRRAF) adopts a cyclic structure via a...

Preclinical / Traditional Use | Antimicrobial / Immune

Melittin is a 26-amino-acid cationic amphipathic peptide (sequence: GIGAVLKVLTTGLPALISWIKRKRQQ, MW ~2846 g/mol) that constitutes approximately 40-60% of dry honeybee (Apis mellifera) venom.

Mechanism: Melittin is an alpha-helical amphipathic peptide that inserts into lipid bilayers, forming toroidal pores that disrupt membrane integrity.

Basic Science / Endogenous Reference | Antimicrobial / Immune

Histatin-5 is a 24-amino-acid histidine-rich cationic peptide (sequence: DSHAKRHHGYKRKFHEKHHSHRGY, MW ~3036 g/mol) found in human saliva.

Mechanism: Histatin-5 kills Candida albicans through a non-lytic, energy-dependent mechanism. The peptide binds to the fungal cell wall protein Ssa1/2 (a heat shock protein), is internalized via polyamine...

Phase III (Not Approved) | Antimicrobial / Immune

Pexiganan (MSI-78) is a 22-amino-acid synthetic analog of magainin 2, an antimicrobial peptide originally isolated from the skin of the African clawed frog (Xenopus laevis).

Mechanism: Pexiganan is a cationic alpha-helical antimicrobial peptide that kills bacteria through membrane disruption.

Phase III (Not Approved) | Antimicrobial / Immune

Omiganan (MBI 226) is a 12-amino-acid synthetic cationic antimicrobial peptide (sequence: ILRWPWWPWRRK-NH2, MW ~1779 g/mol) derived from indolicidin, a natural antimicrobial peptide from bovine neutrophils.

Mechanism: Omiganan is a tryptophan- and arginine-rich cationic peptide that disrupts microbial cell membranes through electrostatic and hydrophobic interactions.

Phase II Clinical Trials | Antimicrobial / Immune

Brilacidin (PMX-30063) is a synthetic small-molecule defensin-mimetic (MW ~564 g/mol) developed by Innovation Pharmaceuticals (formerly Cellceutix).

Mechanism: Brilacidin is an arylamide foldamer that mimics the cationic amphipathic structure of natural defensins.

FDA Approved | Antiviral / HIV

Enfuvirtide is a 36-amino-acid synthetic peptide (MW ~4492 g/mol) that inhibits HIV-1 entry into host cells by blocking the fusion of viral and cellular membranes.

Mechanism: Enfuvirtide mimics the heptad repeat 2 (HR2) region of the HIV-1 gp41 transmembrane glycoprotein. During HIV entry, the viral gp120 protein binds to CD4 and a coreceptor (CCR5 or CXCR4), triggering a...