title: Kappa-flavitoxin: isolation of a new neuronal nicotinic receptor antagonist that is structurally related to kappa-bungarotoxin.
abstract: A peptide, termed kappa-flavitoxin (kappa-flavitoxin), has been purified from the venom of the red-headed krait, Bungarus flaviceps, by low- and high-pressure liquid chromatography. kappa-Flavitoxin has a pI of 8.8 and an apparent molecular weight on sodium dodecyl-sulfate-polyacrylamide gel electrophoresis of 6500 Da. kappa-Flavitoxin is a potent inhibitor of nicotinic transmission in autonomic ganglia, producing a complete and long-lasting blockade at doses as low as 50 nM. Intracellular recordings reveal a selective blockade of neuronal nicotinic receptors by the toxin, with no effects on other active or passive properties of neuronal membranes. kappa-Flavitoxin shares a number of pharmacological and biochemical properties with kappa-bungarotoxin, purified from the venom of Bungarus multicinctus. The two peptides exhibit considerable homology in their amino acid sequences. Radiolabeled kappa-flavitoxin binds to a nicotinic site in ciliary ganglia previously identified by kappa-bungarotoxin, which appears to be associated with the neuronal nicotinic receptor. This site is not recognized by alpha-bungarotoxin, which also does not block nicotinic transmission in this ganglion.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004546:Elapid Venoms / Q000032:analysis* / Q000302:isolation & purification* / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005725:Ganglia, Autonomic / Q000187:drug effects; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D010276:Parasympatholytics / Q000302:isolation & purification* / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000187:drug effects*
chemical_list: D004546:Elapid Venoms; D010276:Parasympatholytics; D011978:Receptors, Nicotinic; C052119:kappa-flavitoxin