Zheng Meihui, Griveau Sophie, Dupont-Gillain Christine, Genet Michel J, Jolivalt Claude
Laboratory Charles Friedel, CNRS UMR 7223, Chimie ParisTech, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05, France.
PSL Research University, Chimie ParisTech, Ecole Nationale Supérieure de Chimie de Paris, Unité de Technologies Chimiques et Biologiques pour la Santé, UMR 8258, INSERM 1022, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05, France.
Bioelectrochemistry. 2015 Dec;106(Pt A):77-87. doi: 10.1016/j.bioelechem.2015.06.004. Epub 2015 Jun 20.
Graphite rods were modified by substituted aryldiazonium salts allowing subsequent laccase immobilisation and direct electron transfer at the cathode. Two covalent enzyme immobilisation methods were performed with carboxy and amino substituted grafted groups, either via the formation of an amide bond or a Schiff base between the glycosidic groups of the enzyme and the amino groups on the electrode surface, respectively. Laccase adsorption efficiency was consistently compared to the covalent attachment method on the same carbon surface, showing that the latter method led to a higher immobilisation yield when the electrode surface was functionalised with carboxylic groups, as shown from both laccase activity measurement towards an organic reducing substrate, ABTS, and quantitative XPS analysis. Both analytical methods led to similar laccase surface coverage estimations. From activity measurements, when laccase was covalently immobilised on the electrode functionalised with carboxylic groups, the surface coverage was found to be 43 ± 2% whereas it was only 10 ± 3% when laccase was adsorbed. Biocatalysed dioxygen reduction current was also higher in the case of covalent immobilisation. For the first time, oxidised laccase performances were compared to unmodified laccase, showing significant improved efficiency when using oxidised laccase: the current obtained with oxidised laccase was 141 ± 37 μA cm(-2) compared to 28 ± 6 μA cm(-2) for unmodified laccase after covalent immobilisation of the enzyme on a graphite electrode functionalised with carboxylic groups.
通过取代芳基重氮盐对石墨棒进行修饰，以便随后固定漆酶并在阴极实现直接电子转移。采用羧基和氨基取代的接枝基团进行了两种共价酶固定方法，分别是通过在酶的糖苷基团与电极表面的氨基之间形成酰胺键或席夫碱。在相同的碳表面上，始终将漆酶吸附效率与共价连接方法进行比较，结果表明，当电极表面用羧基官能化时，后一种方法导致更高的固定化产率，这从漆酶对有机还原底物ABTS的活性测量以及定量XPS分析中都可以看出。两种分析方法得出的漆酶表面覆盖率估计值相似。从活性测量结果来看，当漆酶共价固定在羧基官能化的电极上时，表面覆盖率为43±2%，而漆酶吸附时表面覆盖率仅为10±3%。在共价固定的情况下，生物催化的双氧还原电流也更高。首次将氧化漆酶的性能与未修饰的漆酶进行比较，结果表明使用氧化漆酶时效率显著提高：在将酶共价固定在羧基官能化的石墨电极上后，氧化漆酶获得的电流为141±37μA cm(-2)，而未修饰的漆酶为28±6μA cm(-2)。
