Building Localized NADP(H) Recycling Circuits to Advance Enzyme Cascadetronics

Area of Science:

• Bioelectrochemistry
• Enzyme catalysis
• Nanomaterials

Background:

• Enzyme cascades are crucial for metabolic processes.
• Controlling enzyme activity electrochemically offers precise reaction management.
• Nicotinamide cofactors (NAD(P)H) are vital electron carriers in biological redox reactions.

Purpose of the Study:

• To demonstrate simultaneous electrochemical control and observation of enzyme cascades.
• To utilize reversible electrochemical nicotinamide cofactor recycling for energy and control.
• To showcase the ability to perform reactions under opposing conditions using hydrogen-borrowing enzymes.

Main Methods:

• Confining enzyme cascades within mesoporous electrode materials.
• Employing electrochemical nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) regeneration.
• Incorporating a hydrogen-borrowing enzyme pair to oppose external voltage bias.
• Utilizing a four-enzyme cascade including urease for pathway demonstration.

Main Results:

• Efficient, reversible electrochemical NAD(P)(H) recycling was achieved.
• Multi-step reactions were mediated in either direction with rapid response.
• A reduction process was performed under overall oxidizing conditions, and vice versa.
• Complex metabolic pathways were controlled and resolved, with real-time observation of urease activity under oxidizing potential.

Conclusions:

• Confined enzyme cascades within electrodes can be energized and controlled electrochemically.
• This system allows for the study of anaerobic enzymatic reactions under aerobic conditions.
• The approach mimics electronic circuits, offering a powerful tool for bioelectrocatalysis and metabolic engineering.