Novel Artificial Coenzyme Based on the Viologen Derivative for CO2 Reduction Biocatalyst Formate Dehydrogenase

Formate dehydrogenase (FDH) is an attractive biocatalyst for CO2 reduction. The reduced form of methylviologen acts as an artificial coenzyme for FDH. For further improvement in the CO2 reduction catalytic activity of FDH, a viologen derivative with two amino groups, 1,1'-diaminoethyl-4,4'-bipyridinium salt (DA(2+)), was synthesized as the effective artificial coenzyme for FDH. By enzyme kinetic analysis, the catalytic efficiency, i.e., k(cat)/K-m value of the reduced form of DA(2+) was estimated to be more than 560 times larger than that of NADH, the natural coenzyme for FDH.