PARDAXIN: THE TOXIC FACTOR FROM THE SKIN SECRETION OF THE FLATFISH PARDACHIRUS MARMORATUS (SOLEIDAE)

ABSTRACT The Isolation and purification of the main ichthyotoxic-hemolytic factor, Pardaxin, from the skin secretion of the flatfish Pardachirus marmoratus was performed by gel filtration column chromatography. The purity of this toxin was assessed by disc electrophoresis, ultracentrifugal sedimentation-diffusion as well as amino acid analyses. Pardaxin is an acidic protein composed of 162 amino acids with a mol. wt. of about 17,000 daltons. It is devoid of arginine, histidine and tryptophan and rich in serine, glycine, alanine, leucine, lysine and phenylalanine (responsible for its specific u.v. absorption spectrum). The content of Pardaxin in the crude secretion greatly varies between individual fishes in the range of 20 up to 80 percent of the total proteins.