Decreases the amplitude of the potassium current of the rat channels Kv1.1/KCNA1 by 33% and Kv1.2/KCNA2 by 8% as well as human Kv1.3/KCNA3 by 70%. Expressed by the venom gland. Has the structural arrangement of two alpha-helices stabilized by disulfide bonds (CSalpha/alpha 2(S-S)). Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor kappa-KTx family. Kappa-KTx 2 subfamily. PubMed:15631621 shows two different sequences with Tyr-5 and with Glu-5 (see fig.2 and 4, respectively). The sequence of fig.2 is probably the erroneous one, since table 2 shows a Glu at position 5 and authors mention in the text the lack of aromatic residue on the first helix.