Chemical and pharmacological characterization of toxic polypeptides from the venom of Bungarus caeruleus

Five toxic fractions have been purified to homogeneity from the venom of Bungarus ceruleus by chromatography on CM-Sephadex, QAE-Sephadex and Bio-Rex 70 followed by filtration on Sephadex G-50 and Biogel P-30. One of them blocks synaptic transmission at the pre-synaptic level and is identified as a beta-bungarotoxin similar to that described by Lee from the venom of B. multicinctus. Three other ones are short-chain (type I) alpha-toxins which block the response of the isolated electroplaque from Electrophours electricus to bath-applied carbamylcholine. These basic polypeptides of 61-62 amino acids contain four disulfide bridges. A postsynaptically acting toxin, different from the alpha-toxins, has also been purified from the same venom. This ceruleotoxin is acidic and made up of several subunits.