title: Kunitz-type protease inhibitors from acrorhagi of three species of sea anemones.
abstract: Sea anemones are rich in biologically active polypeptides such as toxins and protease inhibitors. These polypeptides have so far been isolated from whole bodies, tentacles or secreted mucus. Recently, two novel peptide toxins with crab lethality have been isolated from acrorhagi (specialized aggressive organs elaborated by only certain species of sea anemones belonging to the family Actiniidae) of Actinia equina. This prompted us to survey biologically active polypeptides in the acrorhagi of two species of sea anemones, Anthopleura aff. xanthogrammica and Anthopleura fuscoviridis. No potent crab lethality was displayed by the acrorhagial extracts of both species. However, significantly high protease inhibitory activity was instead detected in the acrorhagial extracts of the two species and also in that of A. equina. From the acrorhagi of A. equina, A. aff. xanthogrammica and A. fuscoviridis, one (AEAPI), one (AXAPI) and two (AFAPI-I and AFAPI-III) protease inhibitors were isolated, respectively. The complete amino acid sequences of the four inhibitors were elucidated by N-terminal sequencing and sequencing of the C-terminal peptide fragment produced upon asparaginylendopeptidase digestion. The determined amino acid sequences revealed that all the four inhibitors are new members of the Kunitz-type protease inhibitor family.
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: Sonomi
authors.initials: S
authors.lastname: Minagawa
authors.forename: Miho
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Masami
authors.initials: M
authors.lastname: Ishida
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shiomi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D008969:Molecular Sequence Data; D012615:Sea Anemones / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D007611:Aprotinin