title: Hydrogen peroxide-independent generation of superoxide catalyzed by soybean peroxidase in response to ferrous ion.
abstract: It is well documented that extracellular alkalization occurs in plants under the challenges by pathogenic microbes. This may eventually induce the pH-dependent extracellular peroxidase-mediated oxidative burst at the site of microbial challenges. By employing the purified proteins of horseradish peroxidase as a model, we have recently proposed a likely role for free Fe(2+) in reduction of ferric enzyme of plant peroxidases into ferrous intermediate and oxygen-bound form of enzyme known as Compound III which may eventually releases superoxide anion radical (O2(•-)), especially under alkaline condition, possibly contributing to the plant defense mechanism. In the present study, we employed the purified protein of soybean peroxidase (SBP) as an additional model, and examined the changes in the redox status of enzyme accompanying the generation of O2(•-) in response to Fe(2+) under alkaline condition.
authors.affiliation: a Laboratory of Chemical Biology and Bioengineering; Faculty and Graduate School of Environmental Engineering; The University of Kitakyushu ; Kitakyushu , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kimura
authors.affiliation: a Laboratory of Chemical Biology and Bioengineering; Faculty and Graduate School of Environmental Engineering; The University of Kitakyushu ; Kitakyushu , Japan.|b University of Florence LINV Kitakyushu Research Center (LINV@Kitakyushu); Kitakyushu , Japan.|c Université Paris Diderot; Sorbonne Paris Cité; Paris 7 Interdisciplinary Energy Research Institute (PIERI) ; Paris , France.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kawano
mesh_terms: D055162:Biocatalysis / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007501:Iron / Q000494:pharmacology*; D008954:Models, Biological; D010084:Oxidation-Reduction / Q000187:drug effects; D009195:Peroxidase / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects; D013025:Glycine max / Q000187:drug effects / Q000201:enzymology*; D013431:Sulfates / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
chemical_list: D007477:Ions; D013431:Sulfates; D013481:Superoxides; D006861:Hydrogen Peroxide; D007501:Iron; D009195:Peroxidase; C004850:sodium dithionate
keywords: Compound III; alkalization; auxin; oxidative burst; peroxidase; superoxide