Scyllatoxin

Scyllatoxin (also leiurotoxin I) is a toxin, from the scorpion Leiurus quinquestriatus hebraeus, which blocks small-conductance Ca2+-activated K+ channels.

Charybdotoxin is also found in the venom from the same species of scorpion, and is named after the sea monster Charybdis.

In Greek mythology, Scylla and Charybdis lived on rocks on opposing sides of a narrow strait of water.

[1] Especially the positively charged residues (Arg6 and Arg13, which are located in the ά helix) are important for the expression of toxin biological activities[2] and for its receptor affinity.

[1] Scyllatoxin induces spontaneous contractions in guinea pig taenia coli muscle cells that have been relaxed with epinephrine.