Hemolysins and proteinase inhibitors from sea anemones of the Gulf of Aqaba.

Bioactive polypeptides have been isolated from three sea anemone species by gel filtration and ion-exchange chromatography: hemolysins from Gyrostoma helianthus and Radianthus koseirensis and proteinase inhibitors from the latter species and from Rhodactis rhodostoma. The hemolysins (molecular weight about 10,000) are free of phospholipase A activity, possess considerable ichthyotoxicity, and hemolysis is inhibited by sphingomyelin. The main proteinase inhibitor from Rhodactis rhodostoma is composed of 48 amino acids and inhibits trypsin, kallikrein and chymotrypsin, whereas the semipure inhibitor from Rhadianthus koseirensis has very low affinity for serine proteases and does not inhibit chymotrypsin.