Coelenterolysin: a hemolytic polypeptide associated with the coelenteric fluid of sea anemones

The gastrovascular fluids of the sea anemone Phymactis clematis display strong hemolytic activity, which has basic pH optimum, is thermolabile and is sensitive to proteases. The hemolytic agent from the gastrovascular fluid was partially purified by ammonium sulfate precipitation, chromatography on Dowex-50W cation exchanger and gel filtration on Sephadex G-50. A single peak elutes from the latter with an estimated mol. wt of 18,000. This elution pattern is unaffected if the chromatography is carried out in the presence of 5 M urea. These results indicate that the hemolytic activity is due to a single peptide or a group of peptides of similar size, which we here designate as “coelenterolysin”. Coelenterolysin is also present in sea anemone tissue homogenates, is different from the nematocyst toxin and is not associated with phospholipase activities. It is inhibited by sphingomyelin. This is the first report of hemolytic polypeptides associated with the coelenteric fluid of sea anemones. Coelenterolysin may have a role in extracellular digestion, defense against predators and invasion of the coelenteron by foreign organisms.