This family consists of ergtoxin peptides which are toxins secreted by the scorpions. The ergtoxins are capable of blocking the function of K+ channels. More than 100 ergtoxins have been found from scorpion venoms and they have been classified into three subfamilies according to their primary structures [1].

1: Exploring structural features of the interaction between the scorpion toxinCnErg1 and ERG K+ channels. Frenal K, Xu CQ, Wolff N, Wecker K, Gurrola GB, Zhu SY, Chi CW, Possani LD, Tytgat J, Delepierre M; Proteins 2004;56:367-375. PMID:15211519