Quantitation of amanitins in Amanita verna with calf thymus RNA polymerase B.

A procedure utilizing the specific inhibition of calf thymus DNA-directed RNA polymerase B has been applied to the quantitation of amanitins. This procedure has permitted the accurate quantitation of alpha-amanitin in amounts as low as 0.05 nanogram, a sensitivity 2000-fold greater than chemical detection methods used following tlc. Analysis of extracts of specimens of Amanita verna identified by morphological criteria has demonstrated that while toxin concentration is variable, some specimens are practically devoid of amanitins and may represent a variety of A. verna or a distinct species.