Charybdotoxin, (recombinant)

Charybdotoxin was originally isolated from the venom of the Israeli scorpion Leiurus quinquestriatus hebraeus. Charybdotoxin blocks K_Ca1.1 (large conductance Ca²⁺ activated K⁺, Slo) channels in nanomolar concentrations as as well as K_v1.2 (K_d, 14 nM) and K_v1.3 (K_d, 2.6 nM) channels.). However, experiments with cloned K_Ca1.1 channels demonstrate the strong effect of the slob subunits on the potency of block by Charybdotoxin.