title: Isolation, properties and amino acid sequences of three neurotoxins from the venom of a sea snake, Aipysurus laevis.
abstract: Aipysurus laevis venom was chromatographed on CM-cellulose and Bio-Rex 70 columns. Three neurotoxic components, toxins Aipysurus laevis a, b and c, were isolated. The toxins a, b and c corresponded to 22, 33 and 21% respectively of the proteins in the original venom, and accounted for almost all the lethal activity of the venom. The three toxins a, b and c were monodisperse on disc electrophoresis at pH4; toxins a and b moved at the same velocity and c a little faster. They were monodisperse also on sodium dodecyl sulphate-polyacrylamide-disc-gel electrophoresis, giving a molecular weight of 7600. The molecular weight of toxin b estimated by gel filtration was 7000. The amino acid sequence analyses of these toxins revealed that they consisted of 60 amino acid residues and that Aipysurus laevis b was [25-methionine, 28-arginine] Aipysurus laevis a. Aipysurus laevis c was [28-lysine] Aipysurus laevis a, the tryptic peptide sequence relying on homology. The LD50 values of these toxins for 20g mice were 0.076 mug/g body wt. They inhibited the acetylcholine-induced contracture but did not affect the CKl-induced contracture of the isolated muscle.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D004589:Electrophoresis, Disc; D008970:Molecular Weight; D009132:Muscles / Q000187:drug effects; D010446:Peptide Fragments / Q000032:analysis; D012910:Snake Venoms / Q000032:analysis*; D014118:Toxins, Biological / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology; D014357:Trypsin
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D012910:Snake Venoms; D014118:Toxins, Biological; D014357:Trypsin