Oxygen reduction catalyzed by bilirubin oxidase and applications in biosensors and biofuel cells

Abstract

Bilirubin oxidases (BODs), which is a subclass of the multicopper oxidases (MCOs) family, can reduce O2 to water by receiving electrons from the electrode with almost no overpotential. Therefore, it is an ideal candidate for the reduction of O2 in physiological conditions due to its high tolerance towards chloride anions, high activity, and stability at neutral pH. In this paper, some excellent biochemical properties of BOD were presented by analyzing the crystal structure of the metalloenzyme compared with laccases, such as efficient catalysis and thermotolerance caused by the more compact structure of the protein and/or the deeply buried coppers. Additionally, the applications of BOD in electrochemical fields of biosensors and biofuel cells were summarized and their performances were compared and analyzed cooperating with the different categories of modified materials. As one of the excellent enzymes in MOCs family, BODs are expected to be used in more electrochemical fields with highly efficient biocatalysis ability, and their crystal structures still need to be further explored for better biochemical application.