Bratkovskaya I, Ivanec R, Kulys J
Institute of Biochemistry, Vilnius, LT-08662, Lithuania.
Biochemistry (Mosc). 2006 May;71(5):550-4. doi: 10.1134/s0006297906050130.
The kinetics of oxidation of 4-hydroxybiphenyl (4-HBP) catalyzed by laccase from Polyporus pinsitus was studied in the presence of methyl syringate (MS), which acts as an electron-transfer mediator. Measurements were performed in 0.05 M acetate buffer, pH 5.5, in the presence of 4-HBP, MS, and laccase. It is shown that the oxidation rate of the lowly reactive substrate 4-HBP significantly increases during synergistic action of the highly reactive substrate MS. Bimolecular kinetic constants of interaction between the oxidized form of laccase and MS, the former and 4-HBP, and the oxidized form of MS and 4-HBP were calculated. A kinetic scheme of the synergistic substrate action is suggested; based on this scheme, the dependence of the initial rate on reagent concentration is derived. Analyzing experimental data, we obtained kinetic constants close to those obtained by modeling the processes.
在充当电子转移介质的丁香酸甲酯（MS）存在的情况下，研究了松杉灵芝漆酶催化4-羟基联苯（4-HBP）的氧化动力学。在含有4-HBP、MS和漆酶的0.05M醋酸盐缓冲液（pH 5.5）中进行测量。结果表明，在高反应性底物MS的协同作用下，低反应性底物4-HBP的氧化速率显著增加。计算了漆酶氧化形式与MS、漆酶氧化形式与4-HBP以及MS氧化形式与4-HBP之间相互作用的双分子动力学常数。提出了协同底物作用的动力学方案；基于该方案，得出了初始速率对试剂浓度的依赖性。通过分析实验数据，我们获得了与通过对过程进行建模得到的动力学常数相近的动力学常数。
