Binds specifically to voltage-gated sodium channels (Nav) (site 3), thereby delaying their inactivation during signal transduction (By similarity). Has a strong effect on crustaceans and insects and a weaker effect on mammals (By similarity). It strongly inhibits D.melanogaster sodium channel (DmNav1) (By similarity). It strongly affects the heart sodium channels (Nav1.5/SCN5A) and weakly inhibits the brain sodium channel Nav1.2/SCN2A (By similarity). In vivo, when released into the medium, this recombinant toxin induces impaired swimming, paralysis and death of the crustacean A.nauplii within several hours (PubMed:22048953). Its effect on zebrafish (D.rerio) larvae is much faster, since it induces paralysis or strong convulsion and impaired swimming, within 10 minutes (PubMed:22048953). In nematocyst, is associated with the tubule prior to discharge. Expressed in gland cells and nematocytes. Dose that immobilizes and contracts insects (ED(50)) is 3.7 pmol/g body weight when intersegmentally injected into S.falculata. This protein is encoded by at least 3 different genes. At least 3 other genes code for a similar Av2 with an Ile (instead a Val) at position 35. Belongs to the sea anemone sodium channel inhibitory toxin family. Type I subfamily. Opinions are divided on whether Anemonia viridis (Forsskal, 1775) and Anemonia sulcata (Pennant, 1777) are separate species.