Purification and properties of a toxin from the South African sea anemone, Pseudactinia varia.

A comparison was made of the hemolytic potency of aqueous extracts prepared from five species of intertidal sea anemones from the coast of South Africa. The active agent in an extract of Pseudactinia varia was purified by ammonium sulfate precipitation, gel permeation chromatography and isoelectric focusing. The hemolytic toxin, termed variolysin, is a protein having a molecular weight of 19,500 and an isoelectric pH of 9.8. It retained appreciable activity after heating to 70 degrees for 40 min. Amino acid analysis revealed that it lacked methionine and cysteine. Its hemolytic activity was inhibited by sphingomyelin. The properties of variolysin show that it is broadly similar to cytolytic toxins isolated from a number of other anthozoans.