alpha-Amanitin: inactivation by bovine lactoperoxidase.

The principle amatoxin, alpha-amanitin, is found to be extremely sensitive toward lactoperoxidase catalyzed degradation, rather than iodination, of the indole nucleus. Extensive attenuation of inhibitor potency against eukaryotic DNA-dependent RNA polymerase II accompanies the treatment of alpha-amanitin with lactoperoxidase, iodide and hydrogen peroxide.