title: Snake venom toxins. The amino acid sequences of two toxins (CM-2a and CM-3) from Naja haje annulifera (Egyptian cobra) venom.
abstract: Two toxins, CM-2a and CM-3, were purified from the venom of Naja haje annulifera by gel filtration on Sephadex G-50 and by ion-exchange chromatography on CM-cellulose. Whereas toxin CM-2a contains 61 amino acid residues, toxin CM-3 comprises 60 residues. Both toxins are cross-linked by four intra-chain disulphide bridges. The complete amino acid sequences of the toxins have been elucidated. The properties of the toxins were compared with those of a cytotoxin, a short neurotoxin, a long neurotoxin and an angusticeps type. The sequences of toxin CM-2a and CM-3 and some of the invariant residues do not show a high degree of similarity with those of the other toxins. The toxicities of toxins CM-2a and CM-3 are much lower than those encountered for the cytotoxin or the neurotoxins and their immunochemical properties are distinct from both the cytotoxin and the neurotoxins. They probably represent a new class of toxins.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002918:Chymotrypsin; D004220:Disulfides / Q000032:analysis; D046911:Macromolecular Substances; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D011487:Protein Conformation; D012910:Snake Venoms / Q000302:isolation & purification; D013045:Species Specificity; D014357:Trypsin
chemical_list: D000596:Amino Acids; D004220:Disulfides; D046911:Macromolecular Substances; D010446:Peptide Fragments; D012910:Snake Venoms; D002918:Chymotrypsin; D014357:Trypsin