Improvement of enzyme electrocatalysis using substrate containing electroactive polymers. Towards limiting efficiencies of bioelectrocatalysis

Direct electrocatalysis by the enzymes in the absence of any freely diffusing mediators requires proper orientation of the protein macromolecule on the electrode surface. We report a conception on how to improve efficiency of bioelectrocatalysis using electroactive polymers containing analogues of the enzyme substrates (usually acting as artificial donors-acceptors). Indeed, substrate analogues having affinity to terminal redox groups of the enzymes can anchor them in an optimal orientation upon immobilization. The improvement of bioelectrocatalysis using such electroactive polymers is reported for different enzymes: hydrogenases and cellobiose dehydrogenase. Highly efficient electrocatalysis by hydrogenases was determined by thermodynamics of the catalyzed reaction confirming the direct bioelectrocatalysis. For hydrogenases immobilized over viologen substituted conducting polymers the limiting performance characteristics in bioelectrocatalysis have been achieved. (C) 2009 Elsevier Ltd. All rights reserved.