Bioelectrocatalysis of Pyruvate with PQQ-dependent Pyruvate Dehydrogenase

摘要

Bioelectrocatalysis is the use of a biological entity to catalyze a redox reaction at an electrode. The biological entity employed as a catalyst could be an enzyme (protein), an organelle, or a complete living cell. Enzymes are efficient catalysts and due to their size, higher catalyst loading is possible, which typically results in higher volumetric catalytic activity. In addition, enzymes are not living entities and do not require media to maintain activity(l). Enzymatic bioelectrocatalysis can be broken down into two main types: mediated bioelectrocatalysis and direct bioelectrocatalysis(2). Direct bioelectrocatalysis involves the ability of the enzyme to directly transfer electrons with the electrode, whereas mediated bioelectrocatalysis involves the use of additional redox species that mediated the electron transfer between the enzyme and the electrode. For simplicity sake, researchers have been interested in direct bioelectrocatalysis, but this has been difficult due to the limitations of enzymes capable of this type of electron transfer, because most enzyme active site is buried in the protein. Several pyrroloquinoline quinone (PQQ)-dependent dehydrogenase enzymes have been shown to undergo direct electron transfer (DET); therefore, this class of enzymes has been of interest to bioelectrochemists.