Proteinase inhibitors from the tropical sea anemone Radianthus macrodactylus: Isolation and characteristic

Two new serine proteinase inhibitors (Rmln I and Rmln II) from the tropical sea anemone Radianthus macrodactylus have been isolated and characterized. The purification procedure includes polychrome-1 hydrophobic chromatography, Superdex (TM) Peptide 10/30 FPLC, and Nucleosil C-18 reverse-phase HPLC. The moleclular masses of Rmln 1, Rmln II, and the complexes Rmln II/trypsin and Rmln I,II/alpha-chymotrypsin have been determined. The K-i values of Rmln I and Rmln II for trypsin and alpha-chymotrypsin have been determined. The polypeptides Rmln I and Rmln II are shown to be nontoxic and to exhibit antihistamine activity. The N-terminal amino acid sequences of Rmln I (GICSEPIVVG PCKAG-) and Rmln II (GSTCLEPKVVG PCKA-) have been determined. A high homology of the amino acid sequences is demonstrated for the proteinase inhibitors produced by such evolutionarily distant species as coelenterates, reptiles, and mammals.