漆树漆酶的催化氧化作用——Ⅴ.漆酶/O₂体系获取半醌自由基的研究

漆树漆酶的催化氧化作用——Ⅴ.漆酶/O 2 体系获取半醌自由基的研究 CATALYZED OXIDATION BY RHUS VERNICIFERA LACCASE Ⅴ.The generation of semiquinone radical using laccase/O 2 system 王光辉 Wang Guanghui Jiang Tao Zhang Changjun Li Jiangquan 1 first-author 江涛 1 张昌军 1 李江泉 1 武汉大学化学系 武汉大学化学系 Department of Chemistry,Wuhan University Department of Chemistry,Wuhan University 利用强吸电子基团使自由电子离域以稳定自由基的方法,通过2,3-二氰基氢醌及其二卤衍生物（DDXQH 2 ,X=H、Cl、Br or Ⅰ）的漆酶催化氧化,建立了一条在静止条件下用漆酶/O 2 体系获取高"稳态"浓度（ > 20μmol）半醌自由基阴离子的有效途径。含二卤的2,3-二氰基氢醌底物产生的半醌自由基阴离子能以离子对形式被乙酸乙酯萃取。研究表明,在半醌自由基的酶法研究中,漆酶/O 2 体系有可能成为一个更有效的酶模型。实验证明,漆酶对底物的催化氧化过程具有鲜明的连串反应特征。 An method for the effective generation of high steady state concentration of semiquinone radicals was established from catalyzed oxidation of 2,3-dicyanohydroquinone（DDHQH 2 ）and its dihalid derivatives（DDCQH 2 ,DDBQH 2 and DDIQH 2 ）by laccase/O 2 system in static condition.These sub- strates contain strong electron with drawing groups,which can cause delocalization of the free elec- tron.ESR hyperfine splitting structure was exhibited that they are semiquinone anion-radicals.When the concentration of DDCQH 2 ,DDBQH 2 and DDIQH 2 was 7.74×10 -5 mol—L -1 ,9.15×10 -5 mol· L -1 and 6.95×10 -5 mol·L -1 ,the steady state concentration of semiquinone anion-radicals could be achieved to 2.54×10 -5 mol·L -1 ,2.67×10 -5 mol·L -1 and 2.12×10 -5 mool·L -1 ,respectively. These semiquinone anion-radicals that generated from DDCQH 2 ,DDCBQH 2 and DDIQH 2 ,could be ex- tracted by EtOAc according to an ion pair form,and have identical wave spectrum character with the chemical synthetic semiquinone radical sodium.These results showed that,the laccase/O 2 system can serve as a good enzyme model.Moreover,it was found by the authors that the laccase-catalyzed oxida- tion of substrates possessed a specificity of consecutive reaction obviously. 漆树漆酶 酶催氧化 半醌自由基阴离子 波谱测定 连串反应 Rhus vernicffera laccase enzymatic oxidation semiquinone anion-radicals spectrometry consecutive reaction Q554 国家自然科学基金(61672102) 1992-04-01 2021-04-01 4