A polypeptide toxin from the coral Goniopora

Abstract
A polypeptide toxin has been isolated from Goniopora coral with an M r of 19000. Goniopora toxin has the following properties: (i) it induces contraction of guinea pig ileum and this contraction is prevented by Ca2+‐channel blockers; (ii) it stimulates 45Ca2+ influx in cardiac cells in culture and this stimulation is abolished by Ca2+‐channel blockers; (iii) it prevents binding of (+)‐[3H]PN 200‐110 to the Ca2+‐channel protein of skeletal muscle T‐tubule membranes. All these results taken together suggest that Goniopora toxin is a Ca2+‐channel activator.