High (BK) or intermediate (IK1) conductance calcium-activated and voltage-gated (Kv1.3) channel blocker. Potent and selective inhibitor of the Ca2+-activated K+ channel present in GH3 anterior pituitary cells and primary bovine aortic smooth muscle cells.
Exhibits the same activity as the natural form of the toxin The single chain peptide iberiotoxin (IbTX) is a selective and reversible inhibitor of high-conductance calcium-activated potassium channels (PK,Ca). It occurs naturally in the venom of the scorpion Buthus tamulus. IbTX also modulates the binding of charybdotoxin (CbTX) to smooth muscle sarcolemmal membranes in a non-competitive manner. IbTX is similar in size to CbTX and shares considerable sequence homology with CbTX. However, IbTX differs in its overall charge in having one fewer basic and four more acidic residues than CbTX.