Welcome to the APD, the original antimicrobial peptide database, first online in 2003. As of Sept 10, 2025, the APD6 contained 5680 peptides, including 3351 natural antimicrobial peptides (AMPs), 1733 synthetic AMPs, and 329 predicted AMPs. Natural AMPs with known sequences and activities cover the six life kingdoms (423 bacteriocins from bacteria, 5 from archaea, 8 from protists, 29 from fungi, 270 from plants, and 2610 from animals. The wheel of function records the following peptide functions/activities:

Antibacterial peptides Antibiofilm peptides Anti-MRSA peptides Anti-TB peptides Anti-endotoxin peptides Anti-toxin peptides Antiviral peptides Anti-HIV peptides Antifungal peptides Anti-Candida peptides Antiparasitic peptides Antimalarial peptides Anticancer peptides Anti-diabetic peptides Wound healing peptides Chemotactic peptides Anti-inflammatory peptides Spermicidal peptides Insecticidal peptides Ion channel inhibitors Protease inhibitors Antioxidant peptides Nematocidal peptides Bacteria-agglutinating peptides Synergistic peptides

Host defense animal peptides (76% of natural peptides): 1806 vertebrate and 803 invertebrate AMPs with known activity. There are 155 human AMPs, 407 biologically active peptides from mammals, 1112 membrane active peptides from amphibians (1033 from frogs and 71 from toads), 158 fish innate immune peptides, 55 reptile peptides, 47 from birds, 680 from arthropods, [397 from insects, 76 from crustaceans, 7 from myriapods, 200 from chelicerata, (45 from spiders, 103 from scorpions)], 54 from molluscs, 6 AMPs from protozoa, and more.

Experiment-determined 3D structures: The 534 unique structures in the APD6 have been unified into four classes (see typical structures above): (1) α-helix: top left: Amphibian magainin II; (2) β-sheet, top right bovine lactoferricin; (3) αβ structure: bottom left: plant-PsD1; (4) non-αβ structure: bottom right: bovine indolicidin.

A powerful database search engine for natural, synthetic, and predicted AMPs: You can search for peptide info using APD ID, peptide name, source organism, life domain/kingdom, peptide family name, amino acid sequence, peptide motif, length, charge, hydrophobic content, chemical modification, PDB ID, 3D structure, structural methods (e.g., NMR), antimicrobial activity, synergistic effects, target microbes, molecular targets, mechanism of action, contributing authors, and year of publication.

The novel antimicrobial peptide information pipeline (AMPIP) for R&D: AMPIP is aimed to facilitate the development of advanced AI predictors for more robust peptide antibiotics. You can go to the APD search interface. Then enter any search term (e.g., antimicrobial robustness, resistance development, peptide stability, in vivo PK, in vitro toxicity, in vivo toxicity, animal model, recombinant production, or clinical trials) in the "Additional information" followed by clicking on "Search". For additional details, please refer to the APD6 paper below.

If you would like to collaborate with or donate to the APD, please contact Dr. Wang via Email:gwang@unmc.edu.

CITE:

APD paper links: APD, APD2, APD3; APD4; APD5; APD6
[1] Wang, G., Schmidt, C., Li, X. and Wang, Z. (2025) APD6: The antimicrobial peptide database is expanded to promote research and development by deploying an unprecedented information pipeline. Nucleic Acids Research, in press. pdf above.
[2] Wang, G., Li, X. and Wang, Z. (2016) APD3: the antimicrobial peptide database as a tool for research and education. Nucleic Acids Research 44, D1087-D1093.
[3] Wang, Z. and Wang, G. (2004) APD: the antimicrobial peptide database. Nucleic Acids Research 32, D590-D592.

Last updated: Sept 2025 | Copyright 2003-present Dept of Pathology, Microbiology & Immunology, UNMC, All Rights Reserved

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