title: Amino-acid sequence of ammodytoxin B partially reveals the location of the site of toxicity of ammodytoxins.
abstract: The complete amino-acid sequence of ammodytoxin B, a presynaptically toxic phospholipase A2 isolated from Vipera ammodytes ammodytes venom, was determined by manual and automated protein sequencing. Ammodytoxin B (i.v. LD50 = 0.58 mg/kg for white mice) is 30-fold less toxic than ammodytoxin A, the most toxic phospholipase isolated from the same venom. The two proteins (each 122 residues long) differ in only 3 residues located in positions 115, 118 and 119 (numbering according to R. Renetseder et al. (1985) J. Biol. Chem. 260, 11627-11634) suggesting that an exposed hydrophobic residue in position 115 and a basic residue in position 118 may be responsible for the increased toxicity of ammodytoxin A and should form at least one part of the site of toxicity in ammodytoxins.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003488:Cyanogen Bromide; D054501:Group II Phospholipases A2; D051379:Mice; D010446:Peptide Fragments / Q000032:analysis; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D013329:Structure-Activity Relationship; D014757:Viper Venoms / Q000633:toxicity
chemical_list: D010446:Peptide Fragments; D014757:Viper Venoms; D010740:Phospholipases; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2; C051125:ammodytoxin B; D003488:Cyanogen Bromide