Peptide-based compounds containing four invariant cycteine 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...http://www.google.es/patents/US5804558?utm_source=gb-gplus-sharePatente US5804558 - Protegrins
