 The whole amino acid residue sequence of HNTX-V is NH2-ECLGFG KGCNPS NDQCCK SANLVC SRKHRW CKYEI-COOH.At the active binding site of HNTX-V, Lys27 and Arg 29 are the most important.Hainantoxins selectively inhibit tetrodotoxin-sensitive (TTX-S) voltage-gated sodium channels (VGSCs).