Margatoxin. A Potent Blocker of Kv1.3 K+�Channels.
Margatoxin was originally isolated from the scorpion Centruroides margaritatus. It is a specific blocker of Kv1.3 channels (IC50~30pM), but it also blocks Kv1.6 and a splice variant of the Drosophila Shaker channels with IC50 of 5 and 150 nM respectively. In Xenopus oocytes the toxin was less potent and inhibited expressed Kv1.3 channels with an apparent IC50 of ~1 nM.
Ion Channel Modulators; K+ Channel Blockers.