Potent inhibitor of the Shaker potassium channels and its mammalian homologs (Kv1.1/KCNA1, Kv1.3/KCNA3, Kv1.6/KCNA6) (Ki<1 nM for all channels) (PubMed:8204618, PubMed:20007782). Also blocks Kv1.2/KCNA2 (IC(50)=26.8 nM) (PubMed:8204618, PubMed:20007782). It also shows a weak interaction with nicotinic acetylcholine receptors (nAChR), suggesting it may weakly inhibit it (PubMed:31276191). Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta). Shows weak blocking activity on KCa3.1/KCNN4 (IC(50)=1152 nM) (PubMed:18042681). Does not block Kv2.1/KCNB1 (Ki >2000 nM) (PubMed:8204618). Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 03 subfamily.