On the Regiospecificity of Vanadium Bromoperoxidase

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• 作者：Jennifer S. Martinez ; Georgia L. Carroll ; Richard A. Tschirret-Guth ; Gereon Altenhoff ; R. Daniel Little ; and Alison Butler
• 刊名：Journal of the American Chemical Society
• 出版年：2001
• 出版时间：April 11, 2001
• 年：2001
• 卷：123
• 期：14
• 页码：3289 - 3294
• 全文大小：75K
• 年卷期：v.123,no.14(April 11, 2001)
• ISSN：1520-5126

文摘

Vanadium haloperoxidase enzymes catalyze the oxidation of halide ions by hydrogen peroxide,producing an oxidized intermediate, which can halogenate an organic substrate or react with a second equivalentof hydrogen peroxide to produce dioxygen. Haloperoxidases are thought to be involved in the biogenesis ofhalogenated natural products isolated from marine organisms, including indoles and terpenes, of which manyare selectively oxidized or halogenated. Little has been shown concerning the ability of the marinehaloperoxidases to catalyze regioselective reactions. Here we report the regiospecific bromoperoxidativeoxidation of 1,3-di-tert-butylindole by V-BrPO from the marine algae Ascophyllum nodosum and Corallinaofficinalis. Both enzymes catalyze the regiospecific oxidation of 1,3-di-tert-butylindole in a reaction requiringboth H₂O₂ and Br^- as substrates, but which produce the unbrominated 1,3-di-tert-butyl-2-indolinone productexclusively, in near quantitative yield (i.e. one H₂O₂ consumed per product). By contrast, reactions with thecontrolled addition of aqueous bromine solution (HOBr = Br₂ = Br₃^-) produce three monobromo and onedibromo-2-indolinone products, all of which differ from the V-BrPO-catalyzed product. Further, reactivitiesof 1,3-di-tert-butyl-2-indolinone with both aqueous bromine and V-BrPO differ significantly and shed lightonto the possible nature of the oxidizing intermediate. This is the first example of a regiospecific brominationby a vanadium haloperoxidase and further extends their usefulness as catalysts.