Electrochemical Studies of CO2 -Reducing Metalloenzymes.

Only two enzymes are capable of directly reducing CO2 : CO dehydrogenase, which produces CO at a [NiFe4 S4 ] active site, and formate dehydrogenase, which produces formate at a mononuclear W or Mo active site. Both metalloenzymes are very rapid, energy-efficient and specific in terms of product. They have been connected to electrodes with two different objectives. A series of studies used protein film electrochemistry to learn about different aspects of the mechanism of these enzymes (reactivity with substrates, inhibitors…). Another series focused on taking advantage of the catalytic performance of these enzymes to build biotechnological devices, from CO2 -reducing electrodes to full photochemical devices performing artificial photosynthesis. Here, we review all these works.