Snake venom toxins. The amino-acid sequences of three toxins (9B, 11 and 12A) from Hemachatus haemachatus (Ringhals) venom.

Three toxins (9B, 11 and 12A) were purified from the venom of Hemachtus haemachatus as described previously. Whereas toxin 11 and 12A comprise 61 amino acid residues, toxin 9B contains 63 residues. All three toxins are cross-linked by four intrachain disulphide bridges. The complete amino acid sequences of these toxins have elucidated. The properties of the toxins were compared with those of the cytotoxin group. The toxicities, the sequences and some of the invariant residues of toxin 11 and 12A resemble the corresponding properties of the cytotoxin group. However their immunochemical properties indicate that they are distinct from both the cytotoxin and neurotoxin groups. The sequence of toxin 9B shows that it is related to the cytotoxins, but its toxicity is much lower than those encountered among members of this group.