Coupled" reaction to determine the rate of glucose oxidase: clinical chemists use the enzyme to investigate glucose oxidase, which often oxidizes glucose to determine glucose concentrations in blood serum or urine, producing peroxide (H2O2) as a by-product. The second reaction is performed by the enzyme peroxidase, which is added to the first reaction. The reaction with the peroxide therein provides a colorimetric signal for the colorless cherry-pink dye (aminopyrine) in the enzyme solution, which is monitored at Amax 500 nm. The color change allows the reaction combination of two reactions to be termed a "coupled" reaction.
6-D-glucose + O2 + H2O -> glucose oxidase -> D-gluconic acid (substrate) + H2O2
H2O2 + peroxidase -> gluconolactone + H2O
These coupled reactions produce the colored product that you will measure in the spectrophotometer. It is important to understand that the glucose oxidase assay mix contains not only the glucose oxidase but also all of the other components of this reaction. What are the additional components in the assay mix (this is a good quiz question)?