The BoP venom was first investigated using HPLC and MALDI-TOF/MS. Further, the HPLC fractions were screened by ELISA with antibodies raised against KTX. These antibodies recognized at least three components toxic in mice by intracerebroventricular injection. They were further pharmacologically characterized by competition using 125I-KTX bound to its specific binding sites on rat brain synaptosomes. A single component (4161?Da) inhibited totally the 125I-KTX binding and with high-affinity (IC50?=?0.1?nM), while the two other components poorly competed with (IC50?>?100?nM). These toxins were sequenced in full by Edman's degradation. The high-affinity ligand (BoPKTX) shares 86 % sequence identity with KTX and was classified as toxin ¦Á-KTx3.17. The two others peptides (BoP1 and BoP2, 4093?Da and 4121?Da, respectively) only differ by a Lys/Arg mutation. Their amino acid sequences were related to Martentoxin, which has been characterized from the Chinese scorpion Buthus martenzi Karch and described as both a BKCa and Kv1.3 blocker. Accordingly, they belong to the ¦Á-KTx16 family.