黄孢原毛平革菌木质素过氧化物酶催化氧化1,2,4,5-四甲氧基苯

Oxidation of 1,2,4,5-tetramethoxybenzene by lignin peroxidase of Phanerochaete chrysosporium.

作者信息

Koduri R S, Whitwam R E, Barr D, Aust S D, Tien M

机构信息

Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802, USA.

出版信息

Arch Biochem Biophys. 1996 Feb 15;326(2):261-5. doi: 10.1006/abbi.1996.0074.

DOI:10.1006/abbi.1996.0074

PMID:8611032

Abstract

We have reinvestigated the lignin peroxidase-catalyzed oxidation of 1,2,4,5-tetramethoxybenzene (TMB) by using presteady-state and steady-state kinetic methods. Our presteady-state kinetic results show that the reaction of compound I with TMB obeyed second order kinetics with a rate constant of 1.1 x 10(7) M-1s-1. The reaction of compound II with TMB exhibits a hyperbolic concentration dependence with a Kd of 16 microM and K = 24 s-1. The stoichiometry of TMB oxidation during steady state is two TMB cation radicals formed per H2O2 consumed. These results clearly show that TMB is a good substrate for both compounds I and II of lignin peroxidase.

摘要

我们通过使用预稳态和稳态动力学方法，重新研究了木质素过氧化物酶催化的1,2,4,5-四甲氧基苯（TMB）氧化反应。我们的预稳态动力学结果表明，化合物I与TMB的反应遵循二级动力学，速率常数为1.1×10⁷ M⁻¹s⁻¹。化合物II与TMB的反应表现出双曲线浓度依赖性，解离常数（Kd）为16 μM，K = 24 s⁻¹。稳态下TMB氧化的化学计量比为每消耗一分子H₂O₂形成两个TMB阳离子自由基。这些结果清楚地表明，TMB是木质素过氧化物酶的化合物I和化合物II的良好底物。