α-Bungarotoxin

A polypeptide composed of 74 amino acids containing 5 disulfide bridges. Blocks neuromuscular transmission by irreversible binding to the motor end-plate acetylcholine receptor (K_d = 1 nM to 1 pM) but does not depress acetylcholine release from motor nerve endings. Blocks nicotine-induced augmentation in intracellular Ca²⁺ in PC12 cells (IC₅₀ = 310 nM). 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).

Blocks neuromuscular transmission by irreversible binding to motor end-plate acetylcholine receptor (K_d = 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).

Cell permeable: no

Kd = 1 pM to 1 nM for motor end-plate acetylcholine receptor

Primary Target
Motor end-plate acetylcholine receptor

Product does not compete with ATP.

Reversible: no

Toxicity: Harmful (C)

H-Ile-Val-Cys³-His-Thr-Thr-Ala-Thr-Ser-Pro-Ile-Ser-Ala-Val-Thr-Cys¹⁶-Pro-Pro-Gly-Glu-Asn-Leu-Cys²³-Tyr-Arg-Lys-Met-Trp-Cys²⁹-Asp-Ala-Phe-Cys³³-Ser-Ser-Arg-Gly-Lys-Val-Val-Glu-Leu-Gly-Cys⁴⁴-Ala-Ala-Thr-Cys⁴⁸-Pro-Ser-Lys-Lys-Pro-Tyr-Glu-Glu-Val-Thr-Cys⁵⁹-Cys⁶⁰-Ser-Thr-Asp-Lys-Cys⁶⁵-Asn-Pro-His-Pro-Lys-Gln-Arg-Pro-Gly-OH (disulfide bonds: 3 → 23; 16 → 44; 29 → 33; 48 → 59; 60 → 65)

Supplied as an acetate salt

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.

Contaminants: None detectable by IEF

Lopez, M.G., et al. 1998. Proc. Natl. Acad. Sci. USA 95, 14184.
Zhang, Z.W., et al. 1994. Neuron 12, 167.
Bambrick, L.L., and Gordon, T. 1992. J. Physiol.449, 479.
Lin, S.R., and Chang, C.C. 1992. Biochim. Biophys. Acta1159, 255.
Motomura, M., et al. 1992. Neurosci. Lett.143, 139.
Sorenson, E.M., and Chiappinelli, V.A. 1992. J. Comp. Neurol.323, 1.
Ruan, K.H., et al. 1990. Proc. Natl. Acad. Sci. USA87, 6156.

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