In glucose oxidase-based enzymatic assays, hydrogen peroxide participates in the detection step by reacting with a chromogen to produce color. Which statement best describes this role?

• A. It is reduced to water with no color change
• B. It directly oxidizes the chromogen to a colored product
• C. It participates in a color-producing reaction with a chromogen
• D. It is not involved in detection

Answer: (C)

Hydrogen peroxide acts as the oxidizing partner in the detection step. In these assays, glucose oxidase produces H2O2 from glucose, and a peroxidase enzyme uses that H2O2 to oxidize a chromogenic substrate. The oxidized chromogen becomes colored, so the color intensity reflects how much hydrogen peroxide—and thus how much glucose was present. This is why the correct description is that hydrogen peroxide participates in a color-producing reaction with the chromogen via peroxidase. It isn’t simply reduced to water, and it doesn’t directly oxidize the chromogen on its own, and it is not absent from detection.