Parasin I

Parasin I is a potent 19-residue antimicrobial peptide isolated from the skin mucus of wounded catfish (Parasilurus asotus). Eighteen of the 19 residues in parasin I are identical to the N-terminus of buforin I, a 39-residue antimicrobial peptide derived from the N-terminus of toad histone H2A. This implies that parasin I is cleaved off of the N-terminus of catfish histone H2A. Parasin I shows strong antimicrobial activity, about 12-100 times as strong as magainin 2, against a wide spectrum of microorganisms, without any hemolytic activity. Furthermore, parasin I shows good antimicrobial activity against fish-specific bacterial pathogens.