Some physico-chemical properties of phallolysin obtained from Amanita phalloides

The molecular weight of phallolysin, the toxic haemolysin from Amanita phalloides, was established by gel chromatography to be 30000 daltons. The isoelectric point (I.P.) was found in Ampholine pH 7-10 at 8.34. In Ampholine pH 7-9 the gel chromatographically homogeneous phallolysin was separated into phallolysin A (I.P. 8.06) and phallolysin B (I.P. 7.49). Sodium dodecylsulphate-polyacrylamide gel electrophoresis indicated a molecular weight of 33000 daltons for phallolysin A. Phallolysin was thermo- and acid-labile. It was relatively stable in alkaline solutions. 8 M urea as well as 0.1% sodium dodecylsulphate caused irreversible denaturation. On the other hand, phallolysin showed resistance to diverse proteases (pepsin, trypsin, alpha-chymotrypsin, subtilisin, pronase E, bromelin, proteinase K) and also alpha-amylase and pancreatin. Treatment with proteinase K did not change the molecular weight and the isoelectric points of phallolysin. Resistance to proteases was not due to inhibition of proteases by phallolysin.