Interdisciplinary Nanoscience Center, Science and Technology, Aarhus University, Gustav Wieds Vej 1590-14, 8000 Aarhus C, Denmark.
Chemphyschem. 2013 Jul 22;14(10):2112-24. doi: 10.1002/cphc.201300069. Epub 2013 Apr 15.
Bacterial laccase from Streptomyces coelicolor (SLAC) has been immobilised and orientated at promoter (pyrene and neocuproine)-modified electrodes productively both for direct electron transfer (ET) between the electrode and the T1 Cu site of SLAC and direct (unmediated) bio-electrocatalysis of dioxygen reduction. Its T1 Cu potential ranges between 471 and 318 mV versus the normal hydrogen electrode, at pH 5.5 and 8, respectively; this value is dependent both on the solution pH and electrode modification. In the presence of O2, Cu of the T2/T3 trinuclear centre is distinguished electrochemically at 748-623 mV. Depending on the promoter nature, different orientations of SLAC at pyrene- and neocuproine-modified electrodes can be followed from the kinetic analysis of the ET rates. Bio-electrocatalytic reduction of oxygen starts from the T1 Cu potentials of SLAC, and is most efficient at the promoter-modified electrodes, thereby demonstrating good performance both in neutral and basic media and in solutions with a high NaCl content, such as sea water. The obtained results allow consideration of a broader bioenergetic application of laccases as biocathodes operating directly in such environmental media as sea water and physiological fluids.
细菌漆酶从变铅青链霉菌（SLAC）已固定和定向在启动子（芘和新铜试剂） - 生产性改性电极之间的直接电子转移（ET）电极和 T1 Cu 位的 SLAC 和直接（无中介）生物电催化氧气还原。其 T1 Cu 势范围在 471 到 318 mV 相对于标准氢电极，分别在 pH 5.5 和 8 下；该值取决于溶液 pH 值和电极修饰。在 O2 的存在下，T2/T3 三核中心的 Cu 在 748-623 mV 处可电化学区分。根据促进剂的性质，可以从 ET 速率的动力学分析中跟踪 SLAC 在芘和新铜试剂修饰电极上的不同取向。氧的生物电化学还原从 SLAC 的 T1 Cu 电势开始，并在促进剂修饰电极上最有效，从而在中性和碱性介质以及海水中等具有高 NaCl 含量的溶液中表现出良好的性能。所获得的结果允许考虑更广泛的生物能量应用的漆酶作为生物阴极直接在海水中和生理流体等环境介质中操作。
