Peptide Database
265 therapeutic peptides with research summaries, clinical findings, and regulatory status.
Enfuvirtide (Fuzeon)
A 36-amino acid synthetic peptide that inhibits HIV-1 entry into CD4+ T-cells by blocking the gp41-mediated membrane fusion step. Enfuvirtide binds to the first heptad repeat (HR1) region of gp41, preventing the conformational change required for viral-cell membrane fusion. It is the first and only FDA-approved fusion inhibitor and is active against HIV-1 strains resistant to other antiretroviral drug classes.
Magainin 2
Magainin 2 is a 23-amino acid antimicrobial peptide originally isolated from the skin of the African clawed frog Xenopus laevis. It exerts broad-spectrum antimicrobial activity through membrane disruption, forming pores in bacterial membranes while exhibiting relative selectivity over mammalian cells. Magainin 2 belongs to the alpha-helical cationic antimicrobial peptide family and has served as a template for numerous synthetic analogs. Its mechanism of action, which is distinct from conventional antibiotics, offers potential against multidrug-resistant pathogens.
Pexiganan (MSI-78)
Pexiganan is a 22-amino acid synthetic analog of magainin 2 designed to enhance antimicrobial potency and proteolytic stability. It disrupts bacterial membranes through electrostatic interaction and pore formation, demonstrating broad-spectrum activity against gram-positive and gram-negative organisms, including methicillin-resistant Staphylococcus aureus. Pexiganan was developed as a topical agent for infected diabetic foot ulcers, leveraging its rapid bactericidal action and low resistance potential. Structural modifications from the parent magainin sequence improve its pharmacological profile for clinical use.
Omiganan
Omiganan is a synthetic 12-amino acid cationic antimicrobial peptide derived from indolicidin, a naturally occurring peptide from bovine neutrophils. It acts by disrupting microbial membranes and demonstrates activity against bacteria, fungi, and some viruses. Omiganan was developed as a topical agent to prevent catheter-related bloodstream infections through its broad-spectrum antimicrobial properties. Its small size and potent activity made it a candidate for preventing biofilm formation on medical devices.
Iseganan (IB-367)
Iseganan is a 17-amino acid synthetic analog of protegrin, a naturally occurring antimicrobial peptide found in porcine leukocytes. It disrupts microbial cell membranes via a beta-sheet structure stabilized by disulfide bonds, conferring broad-spectrum activity against bacteria, fungi, and some viruses. Iseganan was developed primarily as an oral rinse to prevent ventilator-associated pneumonia and oral mucositis in immunocompromised patients. Its rapid microbicidal action and low systemic absorption profile supported its formulation for topical oral use.
Defensin HNP-1
Human neutrophil peptide 1 (HNP-1) is a 30-amino acid alpha-defensin produced by neutrophils as part of the innate immune response. It contains three stabilizing disulfide bonds and forms amphipathic structures that disrupt microbial membranes through electrostatic and hydrophobic interactions. HNP-1 exhibits antimicrobial activity against bacteria, fungi, and enveloped viruses, and also modulates immune cell function and inflammatory responses. As an endogenous peptide, it has been studied for potential therapeutic augmentation in immunocompromised states and chronic infections.
Alpha-Defensin 5
Alpha-defensin 5 (HD5) is a 32-amino acid cationic peptide predominantly expressed by Paneth cells in the small intestinal crypts. It contains three disulfide bonds that stabilize its beta-sheet structure and enable membrane disruption of bacteria, fungi, and some viruses. HD5 plays a critical role in maintaining intestinal homeostasis by regulating gut microbiota composition and protecting the epithelial barrier. Altered HD5 expression has been implicated in inflammatory bowel disease, necrotizing enterocolitis, and susceptibility to enteric infections.
Lactoferricin
Lactoferricin is a cationic antimicrobial peptide derived from pepsin-mediated cleavage of lactoferrin, an iron-binding glycoprotein found in milk and mucosal secretions. The most studied variant, bovine lactoferricin B, is a 25-amino acid peptide that disrupts microbial membranes and chelates iron, contributing to its broad-spectrum antimicrobial activity. Lactoferricin exhibits antibacterial, antifungal, antiviral, and antiparasitic properties, along with immunomodulatory effects. Its natural origin and multifunctional activity have generated interest in food preservation, oral health, and topical antimicrobial applications.
Nisin
Nisin is a 34-amino acid polycyclic antibacterial peptide (lantibiotic) produced by Lactococcus lactis. It disrupts bacterial cell wall synthesis and forms pores in cell membranes by binding to lipid II, a precursor essential for peptidoglycan assembly. Its activity is primarily directed against Gram-positive bacteria, making it valuable in food preservation applications. The peptide contains unusual amino acids including lanthionine and beta-methyllanthionine, which confer structural stability and antimicrobial potency.
Gramicidin S
Gramicidin S is a cyclic decapeptide antibiotic isolated from Bacillus brevis, consisting of two identical pentapeptide sequences joined in a ring structure. The peptide exerts antimicrobial activity by disrupting bacterial cell membrane integrity through interaction with phospholipid bilayers, leading to leakage of cellular contents. Its amphipathic beta-sheet conformation enables selective insertion into bacterial membranes. The compound demonstrates broad-spectrum activity against both Gram-positive and Gram-negative organisms.
Polymyxin B
Polymyxin B is a cyclic lipopeptide antibiotic derived from Bacillus polymyxa, consisting of a heptapeptide ring and a tripeptide side chain acylated with a fatty acid tail. The molecule binds to lipopolysaccharide in the outer membrane of Gram-negative bacteria, causing membrane permeabilization and cell death. Its cationic residues interact electrostatically with anionic phosphate groups on lipid A. Polymyxin B is reserved for serious infections caused by multidrug-resistant Gram-negative pathogens when other options are unavailable.
Colistin (Polymyxin E)
Colistin, also known as polymyxin E, is a cyclic polypeptide antibiotic structurally similar to polymyxin B, produced by Paenibacillus polymyxa. It disrupts the bacterial cell membrane by binding to lipopolysaccharide and displacing divalent cations, leading to increased permeability and cell lysis. The compound is administered as colistimethate sodium, an inactive prodrug that is hydrolyzed in vivo to the active colistin base. Its spectrum targets Gram-negative bacteria, particularly Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae.
Indolicidin
Indolicidin is a 13-amino acid antimicrobial peptide derived from bovine neutrophils, characterized by a high tryptophan content (five residues). It exerts antimicrobial activity through multiple mechanisms, including membrane disruption, DNA binding, and inhibition of intracellular processes. The peptide adopts an extended wedge-shaped conformation that facilitates insertion into lipid bilayers. Indolicidin demonstrates activity against bacteria, fungi, and certain protozoa, though its clinical development has been limited by cytotoxicity.