Glucose oxidase catalyzes the oxidation of glucose from D-glucose to D-glucono-d-lactone. Physiologically, it aids in the breakdown of glucose into smaller metabolites. It is widely used in electrochemical glucose sensors designed for diabetes patients. Simple, direct and high-throughput assays for measuring glucose oxidase activity find wide applications in research and drug discovery. This glucose oxidase assay kit uses a single Working Reagent that combines the glucose oxidase reaction and color reaction in one step. The change in color intensity of the reaction product at 570 nm or fluorescence intensity at lambda ex/em = 530/585 nm is directly proportional to glucose oxidase activity in the sample.