Volvatoxin A2, a pore-forming cardiotoxic protein, was isolated from the edible mushroomVolvariella volvacea. Previous studies have demonstrated that volvatoxin A consists of volvatoxin A2 and volvatoxin A1, and the hemolytic activity of volvatoxin A2 is completely abolished by volvatoxin A1 at a volvatoxin A2⁄volvatoxin A1 molar ratio of 2.