With more enzyme activity the optical density

With more enzyme activity the optical density

• A. decreased
• B. stayed the same
• C. not measurable
• D. increased

Answer: (D)

In a colorimetric enzyme assay, optical density rises as the colored product builds up. More enzyme activity means substrates are converted to this colored product faster, so at a given time there is more product present and more light absorption occurs. That higher product concentration translates directly into a higher absorbance reading. If the setup uses a colored product, increased enzyme activity will make the optical density go up. (If the assay depended on consuming a colored reactant like NADH, you’d see a decrease instead, but in this case the product’s color drives a higher OD.)

In a colorimetric enzyme assay, optical density rises as the colored product builds up. More enzyme activity means substrates are converted to this colored product faster, so at a given time there is more product present and more light absorption occurs. That higher product concentration translates directly into a higher absorbance reading. If the setup uses a colored product, increased enzyme activity will make the optical density go up. (If the assay depended on consuming a colored reactant like NADH, you’d see a decrease instead, but in this case the product’s color drives a higher OD.)