Deracemisation and stereoinversion by a nanoconfined bidirectional enzyme cascade: dual control by electrochemistry and selective metal ion activation.

The unique ability of the 'electrochemical leaf' (e-Leaf) to drive and control nanoconfined enzyme cascades bidirectionally, while directly monitoring their rate in real-time as electrical current, is exploited to achieve deracemisation and stereoinversion of secondary alcohols using a single electrode in one pot. Two alcohol dehydrogenase enzymes with opposing enantioselectivities, from (selective for ) and (selective for ) are driven bidirectionally coupling to the fast and quasi-reversible interconversion of NADP/NADPH catalysed by ferredoxin NADP reductase - all enzymes being co-entrapped in a nanoporous indium tin oxide electrode. Activity of the enzyme depends on the binding of a non-catalytic Mg, allowing it to be switched off after an oxidative half-cycle, by adding EDTA - the -selective enzyme, with a tightly-bound Zn, remaining fully active. Racemate → or → conversions are thus achieved in high yield with unprecedented ease.