Synonyms: a-Amanitin, 4-(2-mercapto-L-tryptophan)-;9,18-(Iminoethaniminoethaniminoethaniminomethano)pyrrolo[1',2':8,9][1,5,8,11,14]thiatetraazacyclooctadecino[18,17-b]indole,cyclic peptide deriv.;Cyclo[L-asparaginyl-4-hydroxy-L-prolyl-(R)-4,5-dihydroxy-L-isoleucyl-2-mercapto-L-tryptophylglycyl-L-isoleucylglycyl-L-cysteinyl],cyclic (4®8)-sulfide, (R)-S-oxide