Single polypeptide weight; molecular
weight of 8000.
A protein that binds specifically to acetylcholine
receptors.
Blocks neuromuscular transmission by irreversible binding to motor end-plate acetylcholine receptor (Kd = 1 pM to 1 nM) but does not depress acetylcholine release from motor nerve endings. Blocks nicotine-induced increase of intracellular Ca2+ in PC12 cells (IC50 = 310 nM), and prevents opening of nicotinic receptor-associated ion channels. Reconstitution experiments in Xenopus oocytes have shown the effects of α-bungarotoxin on neuronal nAChR to be highly specific for the α7-subtype (IC50 = 1.6 nM), but not for the α3β4-subtype (IC50 >3 μM).
Product does not compete with ATP.
