熔點245 °C (decomp)

毒性A drug derived from the highly poisonous fungus Amanita phalloides (death cap). Alpha-amanitin, a cyclic octapeptide, is toxic because of its affinity for RNA polymerase II in eukaryotic cells. Since this enzyme is responsible for mRNA synthesis in the cell, the compound is a potent and selective inhibitor of mRNA synthesis. It is effective at concentrations below 1 μg/mL, and its specific action has made it useful in experimental biology. It is often used with actinomycin D to block RNA synthesis.