The compounds have a similar structure, that of eight amino-acid residues arranged in a conserved macrobicyclic motif (an overall pentacyclic structure when counting the rings inherent in the proline and tryptophan-derived residues); they were isolated in 1941 by Heinrich O. Wieland and Rudolf Hallermayer. All<unk> s are oligopeptides that are synthesized as 35-amino-acid proproteins, from which the final eight amino acids are cleaved by a prolyl oligopeptidase. The schematic amino acid sequence of<unk> s is Ile-Trp-Gly-Ile-Gly-Cys-Asn-Pro with cross-linking between Trp and Cys via the sulfoxide (S=O) moiety and hydroxylation in variants of the molecule. The backbone structure (black) is the same in all the<unk> s and five variable groups (red) determine the specific compound. There are currently ten known<unk> s: Name R1 R2 R3 R4 R5 α-Amanitin OH OH NH2 OH OH β-Amanitin OH OH OH OH OH γ-Amanitin OH H NH2 OH OH ε-Amanitin OH H OH OH OH Amanullin H H NH2 OH OH Amanullinic acid H H OH OH OH Amaninamide OH OH NH2 H OH Amanin OH OH OH H OH Proamanullin H H NH2 OH H δ-Amanitin has been reported, but its chemical structure has not been determined.
Amatoxin
Phoratoxin
Aflatoxin
Bukatoxin
Brevetoxin
Eoxin
Ciguatoxin
Dortoxin