The Mechanism of Metal-Containing Formate Dehydrogenases Revisited: The Formation of Bicarbonate as Product Intermediate Provides Evidence for an Oxygen Atom Transfer Mechanism

Mo/W-containing formate dehydrogenases (FDH) catalyzed the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active sites. While in the reaction of formate oxidation, the product is CO2, which exits the active site via a hydrophobic channel; bicarbonate is formed as the first intermediate during the reaction at the active site. Other than what has been previously reported, bicarbonate is formed after an oxygen atom transfer reaction, transferring the oxygen from water to formate and a subsequent proton-coupled electron transfer or hydride transfer reaction involving the sulfido ligand as acceptor.

Automated summary

This study investigates the reversible oxidation of formate to carbon dioxide catalyzed by molybdenum or tungsten-containing formate dehydrogenases. The formation of bicarbonate as the first intermediate during the reaction at the active site is discovered, contrary to previous reports. Bicarbonate formation occurs after an oxygen atom transfer reaction, where the oxygen is transferred from water to formate, followed by a proton-coupled electron transfer or hydride transfer reaction involving the sulfido ligand as the acceptor.