Glucose Oxidase A2

Glucose oxidase from Aspergillus niger is a dimer consisting of 2 equal subunits with a molecular mass of 80 kDa each. Each subunit contains one flavin adenine dinulceotide moiety and one iron. The enzyme is a glycoprotein containing ~16% neutral sugar and 2% amino sugars. The enzyme also contains 3 cysteine residues and 8 potential sites for N-linked glycosylation. Glucose oxidase is capable of oxidizing D-aldohexoses, monodeoxy-D-glucoses, and methyl-D-glucoses at varying rates.

Glucose oxidase (GOX) oxidizes D-glucose to D-gluconolactone and hydrogen peroxide. Hydrogen peroxide, the catalytic product of GOX, serves as an anti-bacterial and anti-fungal agent. It is safe and can be used in several industrial applications like baking, dry egg powder production, wine production, gluconic acid production, etc. It possesses electrochemical activity, which makes it extremely important in glucose sensors and in fuel cell applications. Glucose oxidase catalyses the oxidation of β-d-glucose to d-glucono-β-lactone and hydrogen peroxide, with molecular oxygen as an electron acceptor.

One unit will oxidize 1.0 μmole of β-D-glucose to D-gluconolactone and H2O2 per min at pH 5.1 at 35 °C, equivalent to an O₂ uptake of 22.4 μl per min. If the reaction mixture is saturated with oxygen, the activity may increase by up to 100%.