ペルオキシダーゼによるアゾ色素の退色における反応選択性 [in Japanese] Reaction Selectivity on Decoloration of Azo Dyes Catalyzed by Peroxidase [in Japanese]
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An investigation was conducted into the reaction selectivity of azo dye decoloration by peroxidase (POD). The effects of pH and the addition of <i>p</i>-iodophenol on decoloration rate were investigated using 3 types of dye in single-dye and mixed-dye systems. The addition of <i>p</i>-iodophenol accelerated decoloration. In the mixed-dye system, a pH of 8.0 resulted in the highest decoloration rate. HPLC was used to determine the decoloration rate of individual dyes in the mixed-dye system. The decoloration reaction of Orange I proceeded swiftly, decoloration of Orange II was slowed, and decoloration of Orange G was accelerated. The reaction mechanism in the mixed-dye system is considered to be as follows. Orange I reacts much faster than the other dyes, producing radicals immediately after the reaction commences and then decomposing. Meanwhile, since Orange II has a higher oxidation potential than Orange I, the reaction between Orange II and POD begins after completion of the Orange I reaction. The reaction with Orange G, which has a higher oxidation potential than Orange II, commences even later. Some of the Orange II radicals produced undergo radical reactions with Orange G, transferring electrons to Orange G and reverting to Orange II. As a result, the Orange II reaction is inhibited more than in an Orange II-only system. Conversely, when <i>p</i>-iodophenol was introduced into the mixed-dye system, the reaction selectivity was lost as <i>p</i>-iodophenol radicals reacted simultaneously with all 3 dyes.
- Sen-ito Kogyo
Sen-ito Kogyo 64(5), 125-131, 2008-05-10
The Society of Fiber Science and Technology, Japan