The venom of the African scorpion Leiurus quinquestriatus was subjected to high-performance ion-exchange chromatography. Among a large number ( > 25) of Small proteins and other substances, a protein component of approx. 6500 Da was purified. The effect of this toxin was tested on single myelinated nerve fibres of the frog Rana esculenta. Toxin concentrations less than 10 nM produced clear effects. Activation rather than inactivation of the voltage-dependent sodium channel was strongly affected. Thus, this toxin from an African scorpion acts like the β-toxins present in the venom of North American scorpions.
