glucoseoxidase

Glucose oxidase (GOx) is an enzyme that catalyzes the oxidation of β-D-glucose to D-glucono-δ-lactone while reducing molecular oxygen to hydrogen peroxide. The lactone hydrolyzes to gluconic acid in water. GOx is a flavoprotein with a tightly bound flavin adenine dinucleotide (FAD) cofactor and is classified as EC 1.1.3.4, an oxidoreductase acting on the CH-OH group of donors with oxygen as acceptor.

Source and structure: Commercial GOx is typically produced by fermentation of the fungus Aspergillus niger. The enzyme is usually a glycoprotein that forms a homodimer; each subunit (approximately 80 kDa) contains one FAD molecule, giving a dimeric molecular weight near 160 kDa. Glycosylation and proper folding contribute to stability.

Properties and applications: GOx has optimum activity in mildly acidic conditions and at moderate temperatures. In solution, it uses O2 as the electron acceptor, producing H2O2; under low-oxygen conditions, activity can be limited. The hydrogen peroxide byproduct can be detected electrochemically in glucose sensors or exploited for antimicrobial effects. In sensor designs, mediators can improve performance by bypassing oxygen diffusion limits.

Applications: GOx is widely used in glucose biosensors for blood glucose meters and other analytical devices, as well as in the food and packaging industries to remove dissolved oxygen and limit oxidative spoilage. It is valued for glucose specificity, stability, and well-established assay chemistry.