title: Toxins from the venom of the green mamba Dendroaspis angusticeps that inhibit the binding of quinuclidinyl benzilate to muscarinic acetylcholine receptors.
abstract: Two protein toxins that displace the muscarinic antagonist quinuclidinyl benzilate from rat cortex synaptosomal membranes have been isolated from the green mamba (Dendroaspis angusticeps) venom by gel filtration on sephadex G-50, chromatography on the ion-exchangers Bio-Rex 70 and Sulphopropyl-Sephadex C-25 and reversed-phase HPLC. Toxin 1 has 64 amino acids and four disulfides and a formula weight of 7200 and the corresponding values for toxin 2 are 63, 4 and 6840, respectively. Ultracentrifugation gave a molecular weight of 6900 for toxin 1 and 6700 for toxin 2, Quinuclidinyl benzilate that binds to all types of muscarinic cholinergic receptor was displaced to about 50% by both toxins. This partial displacement indicates that the toxins might be specific for one subtype of receptor.
authors.affiliation: Institute of Pharmacology, Biomedical Center, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Adem
authors.forename: A
authors.initials: A
authors.lastname: Asblom
authors.forename: G
authors.initials: G
authors.lastname: Johansson
authors.forename: P M
authors.initials: PM
authors.lastname: Mbugua
authors.forename: E
authors.initials: E
authors.lastname: Karlsson
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004546:Elapid Venoms / Q000032:analysis / Q000302:isolation & purification* / Q000494:pharmacology; D008297:Male; D008970:Molecular Weight; D011812:Quinuclidines / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000378:metabolism; D012911:Snakes; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism; D014118:Toxins, Biological / Q000032:analysis / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D004546:Elapid Venoms; D011812:Quinuclidines; D011976:Receptors, Muscarinic; D014118:Toxins, Biological; D011813:Quinuclidinyl Benzilate