Beta toxins bind voltage-independently at site-4 of sodium channels (Nav) and shift the voltage of activation toward more negative potentials thereby affecting sodium channel activation and promoting spontaneous and repetitive firing (By similarity). This toxin had also a depressive action on the classical calcium current activated at high membrane potentials. This toxin is active on mammals. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. Beta subfamily.