Protegrins

The invention relates to the field of antibiotic peptides. In particular, the invention concerns short peptides, some of which are isolated from porcine leukocytes, that have a wide range of antimicrobial activities. Peptide-based compounds containing four invariant cysteine residues which have been optionally oxidized to contain two intramolecular disulfide bonds, or modified forms where the cysteines are replaced are useful as preservatives and in preventing, treating, or ameliorating viral or microbial infection in animals and plants, and in inactivating endotoxin.