Pyranose-2 oxidases

We provided the first biochemical characterization of a bacterial pyranose 2-oxidase (Mendes et al 2016). Pyranose 2-oxidases, from the glucose-methanol-choline oxidoreductase family, catalyze the oxidation of several aldopyranoses at the C-2 position, coupling it to the reduction of dioxygen to hydrogen peroxide. Pyranose 2-oxidases are particularly interesting for uses in (clinical) biosensors for sugar(s) detection and in synthetic carbohydrate chemistry. P2Ox employ molecular oxygen, a cheap and clean oxidant, and, importantly, are active with both the a- and β-anomers of D-glucose, and not exclusively with β-D-glucose as it is the case for glucose oxidase, accepting furthermore a wide range of aldopyranoses. The purified recombinant AsP2Ox is a 64-kDa monomer containing a non-covalently bound flavin adenine dinucleotide (FAD) cofactor, distinct features as compared with fungal counterparts that are ~ 270 kDa homotetramers with covalent-linked FAD (Mendes et al 2016). The kinetic and biochemical characterization of AsP2Ox enzyme unveiled its versatility for the use of different electron donors and acceptors (oxidizes D-glucose, D-galactose, D-xylose, L-arabinose and D-ribose and reduces both dioxygen and 1,4-benzoquinone). The identification and characterization of AsP2Ox from A. siccitolerans expanded the repertoire of bacterial oxidoreductases with importance in biotechnological and diagnostic applications. The efficiency of AsP2Ox towards glucose oxidation is currently being improved using directed evolution approaches.