Crotamine is a component of the venom of the snakeCro-talus durissus terrificusand it belongs to the myotoxin pro-tein family. It is a 42 amino acid toxin cross-linked by three disulfide bridges and characterized by a mild toxicity (LD50¼820lg per 25 g body weight, . injection) when compared to other members of the same family. Nonethe-less, it possesses a wide spectrum of biological functions.