Oxidation mechanism of black tea pigment theaflavin by peroxidase
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Mechanism of Oxidation by Horseradish Peroxidase Compound
Binding of p-cresol to native horseradish peroxidase was investigated by differential spectrophotometry, and the value lo3 Kdiss = 3 M was obtained at neutral and acid pH; binding is not competitive with that of cyanide and hydroxide. The Soret region spectrum of Compound II of the enzyme was measured in the steady state at pH 4.26, 6.89, and 10.95, and the differences were found to be too smal...
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Horseradish peroxidase catalyses the oxidation of NAD dimers, (NAD)2, to NAD+ in accordance with a reaction that is pH-dependent and requires 1 mol of O2 per 2 mol of (NAD)2. Horseradish peroxidase also catalyses the peroxidation of (NAD)2 to NAD+. In contrast, bacterial NADH peroxidase does not catalyse the peroxidation or the oxidation of (NAD)2. A free-radical mechanism is proposed for both ...
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Sweetclover (Melilotus alba Desr.) contains a soluble enzyme which oxidizes phenylpyruvate with the addition of either a natural cofactor or Mn2+ and dichlorophenol. The final product of oxidation has not been identilied. Phenylpyruvate oxidation is catalyzed also by horseradish peroxidase, and the oxidation is enhanced by the natural cofactor from sweetclover or Mn2+ and dichlorophenol. After ...
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EDTA inhibits horseradish peroxidase (HRP)-catalysed iodide oxidation in a concentration and pH-dependent manner. It is more effective at pH 6 than at lower pH values. A plot of log Kiapp. values as a function of pH yields a sigmoidal curve from which a pKa value of 5.4 can be calculated for an ionizable group on the catalytically active HRP for EDTA inhibition. Among the structural analogues o...
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In this study, decolorization of the diazo dye, Reactive Black 5 (RB5) in a Coprinus cinereus peroxidase-catalyzed reaction has been investigated. A bisubstate kinetic model for the reaction rate based on the Ping-Pong mechanism was assumed for the enzymatic decolorization. Experiment...
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ژورنال
عنوان ژورنال: Tetrahedron Letters
سال: 2015
ISSN: 0040-4039
DOI: 10.1016/j.tetlet.2015.07.037