Some properties of flammutoxin from the edible mushroom Flammulina velutipes.

A cytolytic toxin from the basidiocarps of the edible mushroom Flammulina velutipes was purified to homogeneity. The lysin, flammutoxin, is a single polypeptide chain of Mr 32,000 and pK about 5.4. It contains unusually large amounts of tryptophan, serine and glycine, and few or none of the sulfur-containing amino acids. Erythrocytes of rat, rabbit, guinea pig, man, mouse, cat and dog were sensitive to lysis, in that order, whereas erythrocytes of sheep, ox, goat, swine and horse were largely or completely resistant to lysis. The toxin appears not to be a phospholipase and it was not inhibitable by any of a variety of lipids. Hemolysis probably involves alteration of the erythrocyte membrane, with formation of submicroscopic ion channels, and it appears to be of the osmotic type. In some respects flammutoxin resembles phallolysin, a cytolytic toxin obtained from the mushroom Amanita phalloides.