Spinoxin, a 34-residue peptide neurotoxin extracted from the venom of Heterometrus spinifer, is characterized by four disulfide bridges. It acts as a potent inhibitor of the Kv1.3 potassium channel with an IC 50 value of 63 nM. This compound is regarded as a promising molecular target for the diagnosis and treatment of a range of autoimmune disorders and cancers [1].