[Development of a novel enzyme-redox-mediator system based on a fungal laccase and ruthenium complexes].

The laccase produced by the fungus Coriolus hirsutus has been coordinatively modified with ruthenium complexes [Ru(phpy)(phen)(MeCN)2]PF6 and Ru(bpy)2CO3 under aerobic and anaerobic conditions. The amount of the complexes per enzyme molecule does not depend on the oxygen concentration, equaling 5 for [Ru(phpy)(phen)(MeCN)2]PF6 and 3 for Ru(bpy)2CO3. The pH dependence of the enzymatic activity, thermostability, and catalytical and electrocatalytical properties of the modified laccase are reported. It has been shown that, during the modification, at least one molecule of the ruthenium compound was coordinated near the T1 active center of the laccase, being directly involved in the catalysis and enhancing its efficiency.