| Toxicity | 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. |
