title: Reoxidation and renaturation studies on the main toxin of Naja naja samarensis.
abstract: The main toxin of Naja naja samarensis is a very small and rigid protein (Mr 6850, 8 cysteines). When fully reduced, it regains its native conformation by a mechanism involving a rapid cysteine oxidation and a slower, less temperature-dependent disulfide exchange. In a native-like form of the protein we observed a population whose cysteines were incompletely reoxidized. When intermediates with blocked cysteines were incubated with oxidized and reduced glutathione, the percentage of native-like molecules increased. These findings suggest a multiple folding pathway.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D003039:Cobra Neurotoxin Proteins / Q000378:metabolism*; D004546:Elapid Venoms / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D011489:Protein Denaturation; D013696:Temperature
chemical_list: D000596:Amino Acids; D003039:Cobra Neurotoxin Proteins; D004546:Elapid Venoms; D005978:Glutathione