Glucose Oxidase A1

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 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%.