漆树漆酶的催化氧化作用——Ⅷ.四卤代氢醌的漆酶催化氧化

漆树漆酶的催化氧化作用——Ⅷ.四卤代氢醌的漆酶催化氧化 CATALYZED OXIDATION BY RHUS VERNICIFERA LACCASE——Ⅷ. The Laccase-catalyzed Oxidation of Tetrahalohydraquinone 王光辉 Wang Guanghui 1 2 first-author 江涛 Jiang Tao 1 2 武汉大学化学系 武汉大学化学系 Department of Chemistry,Wuhan University,,. Department of Chemistry,Wuhan University,,. 武汉大学化学系,武汉,430072 武汉大学化学系,武汉,430072 在静止条件下,对四卤代氢醌（TXQH 2 ,X=Cl、Br、I）的漆酶催化氧化行为进行了考察。结果证明,四卤代氢醌的酶反应具有几个明显特征:1)一级离解种是底物参与反应的必要形式;2)半醌自由基阴离子是反应的产物;3)半醌自由基经歧化转变成相应的对醌;4)整个反应过程呈现出连串反应属性。这些特征反映了漆酶催化氧化反应的共性。结果还表明,由于卤原子的吸电子作用不强,不能使自由电子有效地离域,生成的半醌自由基寿命短,衰减快;但在二甘醇存在下,可以有效地延缓半醌自由基的衰减,实现提高半醌自由基动力学稳定性的目的。 The behaviors of Rkus Laccase-catalyzed oxidation reaction of tetrahalohy-droquinone were studied in static condition. The results demonstrated that: （a） the monoan-ion form of substrates is essential species of the reaction;（b） the semiquinone anion-radicals are direct products of the reaction of the substrates; （c） the semiquinone anion-radicals con-verted into tetrahalobenzoquinone through disproportionation reaction ;（d） the whole pro-cess appears the characterization of consecutive reaction. These specific properties reflect the general characfer of Laceace-catalyzed oxidation reaction. The reaults shown that, because the extent of delocalization of free electron through the action of electron withdrawing group of halogen in ring is insufficient,the stability of the generated semiquinone radicals is relativi-ly poor;in the presence of diglycol,the decay of the semiquinone radicals is can delayed effi-ciently,for this reason,the kinetics stability of semiquinone radicals is improved obviously. 漆树漆酶 四卤代氢醌 酶催氧化 半醌自由基的稳定化 波谱测定 rhus vernicifera laccase tetrahalohydroquinone enzymatic oxidation stabi-lization of semiquinone radicals spectral analysis Q554.9 国家自然科学基金资助的课题 1994-06-01 2021-04-01 6