Students measured the initial rate of catalase activity by recording the volume of O2 produced per second when the enzyme was exposed to varying concentrations of hydrogen peroxide. All reactions were run at 25 degrees C and pH 7. The table below shows mean rates from triplicate trials.
Which conclusion is best supported by the data?
- Acheck_circle
The enzyme approaches saturation between 20 and 40 mM substrate.
- B
Rate is directly proportional to substrate at all tested concentrations.
- C
The enzyme is denatured at 40 mM substrate.
- D
The enzyme has greater affinity for product than for substrate.
Explanation
The rate plateaus between 20 mM (4.0) and 40 mM (4.1), indicating active sites are saturated. Linear proportionality fails at high [S]; denaturation would lower the rate.