There are three different phrixotoxins:
Phrixotoxin-1 (PaTx1) – which is composed of 29 amino acids
Phrixotoxin-2 (PaTx2) – which is composed of 31 amino acids
Phrixotoxin-3 (PaurTx3 or Beta-theraphotoxin-Ps1a) – which is composed of 34 amino acids
PaTx1 is 83.3% identical to PATx2, differing only by two acidic residues(Chagot 2004)(Diochot 1999).
Phrixotoxin-1 and -2 are similar to heteropodatoxin, which also has a blocking activity on Kv4.2 channels (Chagot 2004).

Phrixotoxin-1, -2 and -3 contain an Inhibitor Cystine Knot (ICK) motif, and thus belong to the ICK peptide family(Chagot 2004)(Bosmans 2006).
There are three different phrixotoxins:
Phrixotoxin-1 (PaTx1) – which is composed of 29 amino acids
Phrixotoxin-2 (PaTx2) – which is composed of 31 amino acids
Phrixotoxin-3 (PaurTx3 or Beta-theraphotoxin-Ps1a) – which is composed of 34 amino acids
PaTx1 is 83.3% identical to PATx2, differing only by two acidic residues(Chagot 2004)(Diochot 1999). Phrixotoxin-1 and -2 are similar to heteropodatoxin, which also has a blocking activity on Kv4.2 channels (Chagot 2004).
Phrixotoxin-1, -2 and -3 contain an Inhibitor Cystine Knot (ICK) motif, and thus belong to the ICK peptide family(Chagot 2004)(Bosmans 2006).
Phrixotoxin