Which of the following can be used to determine the rate of enzyme-catalyzed reactions?

• A. Calculating the melting temperature of the enzyme
• B. Measuring the change in substrate concentration over time
• C. Determining the pH of the reaction buffer
• D. Measuring the enzyme's molecular weight

Answer: (B)

Verified step by step guidance

1. Understand the concept of enzyme-catalyzed reactions: Enzymes speed up chemical reactions by lowering the activation energy. The rate of an enzyme-catalyzed reaction is typically measured by observing changes in substrate or product concentration over time.
2. Identify the key parameter to measure: The rate of an enzyme-catalyzed reaction is directly related to how quickly the substrate is converted into the product. This is why measuring the change in substrate concentration over time is a valid method.
3. Eliminate irrelevant options: Calculating the melting temperature of the enzyme does not provide information about the reaction rate. Similarly, determining the pH of the reaction buffer or measuring the enzyme's molecular weight are not directly related to the rate of the reaction.
4. Focus on the correct method: To measure the rate, you can monitor the decrease in substrate concentration or the increase in product concentration over time using techniques such as spectrophotometry, chromatography, or other analytical methods.
5. Summarize the reasoning: The correct answer is measuring the change in substrate concentration over time because it directly reflects the activity of the enzyme and the rate at which the reaction occurs.