Kappa-conotoxins inhibits voltage-gated potassium channels (Kv). This synthetic toxin reversibly inhibits the insect potassium channel Shaker K+, the teleost homolog TSha1 and the mammalian Kv1.2/KCNA2 channel. Interacts with the pore region of the insect channel, in a state-dependent manner. Causes seizure when intracerebrovascularly injected into mice. Is also toxic when intrathecally injected into mice, but shows no visible effects by intraperitoneal injection. Shows protective effects on cardiac tissue when administered after an ischemic event. Expressed by the venom duct. The cysteine framework is III (CC-C-C-CC). Classified in the M-4 branch, since 4 residues stand between the fourth and the fifth cysteine residues. Has no or very low potency on Kv1.1/KCNA1, Kv1.3/KCNA3, Kv1.4/KCNA4, Kv1.5/KCNA5, Kv1.6/KCNA6, Kv2.1/KCNB1, Kv3.4/KCNC4, Kv4.2/KCND2, Kv7.2/KCNQ2-Kv7.3/KCNQ3, Kv10.1/KCNH1, Kv11.1/KCNH2, and KCa1.1/KCNMA1. Has no effect on sodium channels (Nav1.2/SCN2A, Nav1.4/SCN4A, and Nav1.5/SCN5A) (PubMed:12399472). Belongs to the conotoxin M superfamily.