Phallolysin

Abstract

With the description of phallolysin, we return to the early beginning of Amanita research. As mentioned on p. 15 of this book, Kobert (1891) detected hemolytic activity in mushrooms of the genus Amanita considered by him as Amanita phalloides, and accordingly, named phallin. He described it as unstable in acids and at temperatures over 65 °C. Since phallin effected lysis of red cells in dilutions as high as 1:125,000, there can be no doubt that Kobert had detected one of the lytic proteins present in several of the Amanitaceae. However, it remains uncertain whether the mushroom sample, which he investigated, was in fact from Amanita phalloides, since he described his “proteid” phallin as also causing hemolysis in bovine erythrocytes. Later, these cells proved to be stable to hemolysin of Amanita phalloides. On the other hand, bovine red cells are sensitive to the hemolysin of Amanita rubescens, and most probably, Kobert had examined extracts of the latter species. A few years later, this work was continued by Abel and Ford (1907). These authors extracted tissue from — what they thought — Amanita phalloides, but most probably, a white Amanita (see p. 15) and achieved a partial purification. They separated the Amanita hemolysin from the toxic peptides by precipitation with ethanol. Their hemolytic fraction was rich in saccharide material, suggesting that the hemolysin was a “glucoside” rather than a “toxalbumin”. Today, we know that the hemolytic substance, called phallolysin, is indeed a protein, but cannot be precipitated by trichloroacetic acid. Interest in this mushroom toxin subsided quickly when it became evident that phallolysin could not possibly contribute to human intoxication, because of its lability during heating and because it would be inactivated by contact with the acid of the gastric juice, if ingested in a crude state. It was not until 1967 that phallolysin was “rediscovered” by Fiume (1967), who used a partially-purified fraction of phallolysin in cytolytic studies. According to Seeger and Wiedmann (1972) and Seeger et al. (1973 b), hemolytic activity is not only present in Amanita phalloides, but also in other Amanita species. It is strongest in Amanita phalloides, weaker in Amanita verna, considerable in Amanita rubescens, but missing in other Amanita species.