Enzymes as modular catalysts for redox half reactions in H2-powered chemical synthesis: from biology to technology

摘要

This article considers the ways in which redox enzyme modules are coupled in living cells for linking reductive andoxidative half reactions, and then reviews examples in which this concept can be exploited technologically inapplications of coupled enzyme pairs. We discuss a number of examples in which enzymes are interfaced withelectronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termedsynthetic biochemistry. We focus on reactions involving the H+/H2 redox couple catalysed by NiFe hydrogenasemoieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialisedchemicals, chemical building blocks or bio-derived fuel molecules. We review our work in which this approach is appliedin designing enzyme modified particles for H2-driven recycling of the nicotinamide cofactor NADH to provide a cleancofactor source for applications of NADH-dependent enzymes in chemical synthesis, presenting a combination ofpublished and new work on these systems. We also consider related photobiocatalytic approaches for light-drivenproduction of chemicals or H2 as a fuel. We emphasise the techniques available for understanding detailed catalyticproperties of the enzymes responsible for individual redox half reactions, and the importance of a fundamentalunderstanding of the enzyme characteristics in enabling effective applications of redox biocatalysis.