Has a toxic effect on insects and mammals. On German cockroach larvae, it provokes contraction, paralysis and lethality (PubMed:26109302). Intracerebroventricular injection into mice causes severe neurotoxic symptoms (PubMed:26109302). It fully competes with the binding of the iodinated Css4 (AC P60266) on rat brain synaptosomes, with moderate affinity and in a concentration-dependent manner (EC(50)=25 nM). It may act on both site 3 and site 4 of voltage-gated sodium channels. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). with pyrrolidone carboxylic acid (Glu). LD(50) is 80 ng/100 mg of body weight cockroach larvae (B.germanica). This toxin does not inhibit the binding of iodinated Css2 (AC P08900) and iodinated Ts1 (AC P15226) to their specific antibodies. Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family.