Blocks voltage-gated potassium channels rKv1.1/KCNA1, rKv1.2/KCNA2, hKv1.3/KCNA3, rKv1.6/KCNA6 (IC(50)=75.9 nM) and, to a lesser extent, Shaker IR (with the inactivation domain removed). Monomer. 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 1 ug/kg by intracerebro-ventricular injection in mice. Does not block voltage-gated potassium channels rKv1.4/KCNA4 and rKv2.1/KCNB1. Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 19 subfamily.