BmP02 is a selective Kv1.3 channel blocker and a highly-selective Kv4.2 modulator, which can be isolated from Chinese scorpion (Buthus martensi Karsch) venom. BmP02 also delays the inactivation of Kv4.2 in HEK293T cells, with an EC 50 value of ~850 nM. BmP02 inhibits the transient outward potassium currents (Ito) in ventricular muscle cells.