Potent inhibitor of voltage-dependent potassium channels, with a preference for Kv1.3/KCNA3 versus Kv1.2/KCNA2. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). LD(50) is 5 ug/kg by intracerebroventricular injection into mice (100 ng/mouse). Has no effect on Kv1.1/KCNA1. Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 03 subfamily.