Beta toxin that binds site-4 of sodium channels (Nav) and reduces peak current (observed on Nav1.6/SCN8A (IC(50)=307 nM)), shifts the voltage of activation toward more negative potentials (observed on Nav1.6, Nav1.1 (weak), Nav1.2 (weak), and Nav1.7 (weak)), and induces resurgent currents at negative voltages following brief and strong depolarizations (observed on Nav1.6, Nav1.1 (weak), and Nav1.7 (weak)) (PubMed:22200496). A reduction of peak current of Nav1.5/SCN7A has been observed in another study (IC(50)=35-40 nM) (PubMed:22251893). This toxin is only active on mammals (PubMed:17544584). It has been shown to bind phospholipids (PubMed:15632158). Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). C-terminal amidation increases its affinity for sodium channels. LD(50) is 25 ug/kg by subcutaneous injection into mice and 0.25 ug/kg by intracerebroventricular injection. LD(100) is 3 ug/kg by intracranial injection into mice. Is the most abundant and deadly toxin from the venom of C.s.suffusus. Does not show inhibition of peak current on Nav1.1, Nav1.2, Nav1.3, Nav1.4, Nav1.5 and Nav1.7 (at 280 nM). Is neutralized by the single-chain antibody fragment 10FG2. Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. Beta subfamily.