title: Covalent structure of toxins I and II from the scorpion Buthus occitanus tunetanus.
abstract: The amino acid sequences of neurotoxins I and II, which are active on mammals, purified from the venom of Buthus occitanus tunetanus have been determined using standard methods, including mainly automatic phenylisothiocyanate degradation of S-carboxymethylated derivatives of the two proteins and peptides derived by enzymatic hydrolyses. Both toxins are made of sixty-five amino acid residues cross-linked with four disulfide bridges. For toxin II, the complete covalent structure, including the positions of the four disulfide bridges was determined: the positions are similar to those previously found in toxin II of another scorpion from Africa, Androctonus australis Hector. This finding is in favor of a similar structure for all of the scorpion neurotoxins active on mammals.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D009498:Neurotoxins / Q000032:analysis*; D012604:Scorpion Venoms / Q000032:analysis*
chemical_list: D009498:Neurotoxins; D012604:Scorpion Venoms