title: Sensitivity of alpha-amanitin to oxidation by a lactoperoxidase-hydrogen peroxide system.
abstract: Oxidation of alpha-amanitin - a potent hepatotoxin found in the mushroom Amanita phalloides - by a lactoperoxidase-hydrogen peroxide system was investigated by different techniques. (i). UV spectroscopy of the mixture after 24 h incubation reveals a significant decrease in the absorbance range characteristic of the putative reactive moiety of the toxin, the tryptathionine group. (ii). Formation of a new product was detected by Thin Layer Chromatography. (iii). In vivo experiments with non-inbred male albino mice showed a lowered toxicity of the modified toxin in comparison with that of the native one. Taking into account the latter results concerning the sensitivity of the toxin towards an oxidising system, the formation and reactivity of an alpha-amanitin derivative is discussed in the course of A. phalloides poisoning (inhibition of RNA polymerase type II and development of damaging radical species).
authors.affiliation: Department of Chemistry and Biochemistry, Medical Faculty, Thracian University, 11 Armeiska Str. 6000, Stara Zagora, Bulgaria.
authors.forename: A
authors.initials: A
authors.lastname: Zheleva
authors.forename: D
authors.initials: D
authors.lastname: Michelot
authors.forename: Z D
authors.initials: ZD
authors.lastname: Zhelev
mesh_terms: D000546:Amanitins / Q000737:chemistry* / Q000633:toxicity; D000818:Animals; D002855:Chromatography, Thin Layer; D005609:Free Radicals / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007202:Indicators and Reagents; D007784:Lactoperoxidase / Q000737:chemistry*; D007928:Lethal Dose 50; D008297:Male; D051379:Mice; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000546:Amanitins; D005609:Free Radicals; D007202:Indicators and Reagents; D006861:Hydrogen Peroxide; D007784:Lactoperoxidase