An NAD(P)H-Dependent Artificial Transfer Hydrogenase for Multienzymatic Cascades.

Area of Science:

• Biocatalysis
• Organometallic Chemistry
• Enzyme Engineering

Background:

• Traditional enzymes use NAD(P)H or FADH2 for reductions.
• Organometallic catalysts commonly use isopropanol or formate for hydride generation.
• A need exists for novel catalysts mimicking enzymatic hydride transfer.

Purpose of the Study:

• To engineer an NAD(P)H-dependent artificial transfer hydrogenase (ATHase).
• To demonstrate the catalytic efficiency of the ATHase in imine reduction.
• To develop a cascade reaction for enantiopure amine production.

Main Methods:

• Incorporation of a Cp*Ir cofactor with biotin and dihydroxyphenanthroline into streptavidin.
• Utilizing the engineered ATHase for imine reduction with NADPH.
• Concurrent regeneration of NADPH using glucose dehydrogenase (GDH) and glucose.
• Constructing a four-enzyme cascade including ATHase, GDH, monoamine oxidase, and catalase.

Main Results:

• The ATHase efficiently catalyzed imine reduction using low concentrations of NADPH.
• NADPH regeneration was achieved using a stoichiometric amount of glucose via GDH.
• A four-enzyme cascade successfully produced enantiopure amines.

Conclusions:

• The developed ATHase represents a novel biocatalytic tool for reduction reactions.
• The cascade system offers a sustainable approach for synthesizing enantiopure amines.
• This work bridges organometallic catalysis and enzymatic hydride transfer.