Purification and Biochemical Characterization of a Beta-Bungarotoxin.

A chromatographic procedure is described for the separation of the neurotoxic proteins in Bungarus multicinctus venom. The most positively charged toxic protein isolated was examined for purity, molecular weight, amino acid composition and toxicity. Nine protein peaks were isolated from the crude venom by column chromatography on CM-Sephadex C-25. Peak IX Beta-IX, the most electropositive protein peak, ran as a single band on pH 4.3 and SDS polyacrylamide gel electrophoresis. Beta-IX was toxic to mice when injected intravenously. Animals which received lethal doses exhibited hyperexcitability followed by ataxia, convulsions and death. Beta-Bungarotoxin acts presynaptically at the neuromuscular junction to inhibit transmitter release. The study of the toxin and its action provide a model system for studying the effects of other forms of stress on neuronal activity.