title: Differential effects of flavonols on inactivation of alpha1-antitrypsin induced by hypohalous acids and the myeloperoxidase-hydrogen peroxide-halide system.
abstract: Alpha1-antitrypsin is well known for its ability to inhibit human neutrophil elastase. Pretreatment of alpha1-antitrypsin with hypohalous acids HOCl and HOBr as well as with the myeloperoxidase-hydrogen peroxide-chloride (or bromide) system inactivated this proteinase. The flavonols rutin, quercetin, myricetin, and kaempferol inhibited the inactivation of alpha1-antitrypsin by HOCl and HOBr with rutin having the most pronounced effect. In contrast, these flavonols did not remove the proteinase inactivation by the myeloperoxidase-hydrogen peroxide-halide system. Taurine did not protect against the inactivation of alpha1-antitrypsin by HOCl, HOBr, or the myeloperoxidase-hydrogen peroxide-halide system, while methionine was efficient in all systems. A close association between myeloperoxidase and alpha1-antitrypsin was revealed by native gel electrophoresis and in-gel peroxidase staining. In addition, alpha1-antitrypsin binds to the myeloperoxidase components transferred after SDS-PAGE on a blotting membrane. With this complex formation, myeloperoxidase overcomes the natural antioxidative protective system of plasma and prevents the inactivation of alpha1-antitrypsin.
authors.affiliation: Laboratory of Applied Biochemistry, Department of Biology, Faculty of Sciences, University of Ferhat ABBAS, 19000 Setif, Algeria.
authors.forename: Hamama
authors.initials: H
authors.lastname: Bouriche
authors.forename: Pavel
authors.initials: P
authors.lastname: Salavei
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lessig
authors.forename: Juergen
authors.initials: J
authors.lastname: Arnhold
mesh_terms: D001959:Bromates / Q000737:chemistry*; D004789:Enzyme Activation; D044948:Flavonols / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006997:Hypochlorous Acid / Q000737:chemistry*; D009195:Peroxidase / Q000737:chemistry*; D000515:alpha 1-Antitrypsin / Q000737:chemistry*
chemical_list: D001959:Bromates; D044948:Flavonols; D006219:Halogens; D000515:alpha 1-Antitrypsin; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D009195:Peroxidase; C027664:hypobromous acid