Naja haje haje (Egyptian cobra) venom. Some properties and the complete primary structure of three toxins (CM-2, CM-11 and CM-12)

Abstract

Three toxins (CM-2, CM-11 and CM-12) were purified from Naja haje haje (Egyptian cobra) venom. Whereas toxin CM-11 contains 65 amino acid residues and five intrachain disulphide bridges, toxin CM-2 and CM-12 comprise, respectively, 61 and 62 residues but both contain four disulphide bridges. The complete primary structures of the three toxins have been established. The sequence and the invarient amino acid residues of CM-2 resemble those of part of a long neurotoxin, a short neurotoxin and a cytotoxin. The sequence of CM-11 reveals that it is a homologue of the neurotoxins and to some extent also a cytotoxin. The immunochemical properties and the sequences of CM-12 suggest that it is related to the cytotoxin group. Further, the sequences of CM-11 and CM-12 from Naja haje haje venom show a high degree of homology with those of the corresponding toxins isolated from NaJA annulifera or NaJA melanoleuca venoms.