title: Purification, characterization and cDNA cloning of two natterin-like toxins from the skin secretion of oriental catfish Plotosus lineatus.
abstract: The oriental catfish Plotosus lineatus is known to contain proteinaceous toxins in the skin secretion as well as in the venom gland. However, detailed properties and primary structures of the skin toxins have not been clarified. In this study, two proteinaceous toxins (toxins I and II) were purified from the skin secretion of oriental catfish by a combination of gel filtration, anion-exchange HPLC and hydroxyapatite HPLC. Toxins I and II are monomeric simple proteins with almost the same molecular mass (35 kDa for toxin I and 37 kDa for toxin II) and are distinguishable from each other in isoelectric point (6.5 for toxin I and 5.1 for toxin II). Both toxins display lethal, edema-forming and nociceptive activities, although toxin I is significantly more potent than toxin II. The primary structures of toxins I and II were elucidated by cloning experiments based on the determined partial amino acid sequences. Toxins I (317 amino acid residues) and II (315 amino acid residues) share as high as 86% sequence identity with each other and are also highly homologous (56-75% identities) with the known fish natterin-like proteins.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Tamura
authors.forename: Miho
authors.initials: M
authors.lastname: Yamakawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shiomi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002397:Catfishes; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D007928:Lethal Dose 50; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008387:Marine Toxins