– αC-Conotoxin PrXA is a neurotoxic paralytic peptide acting as a competitive antagonist of the nicotinic acetylcholine receptor (nAChR), exhibiting inhibitory constants (IC50) of 1.8 nM for the adult α1β1εδ subtype and 3.0 nM for the fetal α1β1γδ subtype. The compound vies with α-bungarotoxin for binding sites at the α/δ and α/γ interfaces of neuromuscular nAChRs, demonstrating high selectivity[1].