Butovich I A, Semichaevskiĭ V D
Ukr Biokhim Zh (1978). 1986 Jul-Aug;58(4):18-26.
Phenol oxidase preparations possessing high stability in the reaction of phenols oxidation are isolated from the culture filtrates of four strains of higher basidiomycete Pleurotus ostreatus (F r.) Kumm. The preparations are able to oxidize mono- and diphenols with different substituents in o-, m- and p-positions to phenol hydroxyls as well as o- and p-phenylene diamines. A change in the orientation of substituents in the substrate molecule is followed by a change in the mechanism of its oxidation. The enzyme activity is determined by the type of substituents in the phenol molecule: electron-withdrawing groups impede and electron-releasing ones facilitate the substrate oxidation. The Hammett equation is shown to be applicable for description of monophenol oxidation. An explanation of high values of positive deviations from it in the case of halogen-substituted phenols is suggested. A conclusion is drawn that Km of enzymes for oxygen determined from the full kinetic curves of O2 uptake with phenol redundancy are kinetic constants depending on the substrate structure.
从四种高等担子菌平菇（F r.）库姆菌株的培养滤液中分离出在酚类氧化反应中具有高稳定性的酚氧化酶制剂。这些制剂能够氧化在酚羟基的邻、间和对位具有不同取代基的单酚和二酚以及邻苯二胺和对苯二胺。底物分子中取代基取向的变化伴随着其氧化机制的改变。酶活性由酚分子中取代基的类型决定：吸电子基团阻碍底物氧化，供电子基团促进底物氧化。哈米特方程被证明适用于描述单酚氧化。针对卤素取代酚情况下其正偏差高值给出了解释。得出结论，从苯酚过量时氧气摄取的完整动力学曲线确定的酶对氧气的Km是取决于底物结构的动力学常数。
