The best way to increase the reaction rate for an enzyme saturated with substrate is always to:

• A. Increase the pH.
• B. Increase the temperature.
• C. Increase [enzyme].
• D. Increase [substrate].

Answer: (C)

Verified step by step guidance

1. Understand the concept of enzyme saturation: When an enzyme is saturated with substrate, it means that all active sites of the enzyme molecules are occupied by substrate molecules, and the reaction rate has reached its maximum.
2. Consider the effect of increasing substrate concentration: Since the enzyme is already saturated, increasing the substrate concentration will not increase the reaction rate further, as there are no free active sites available.
3. Evaluate the impact of increasing enzyme concentration: Adding more enzyme molecules will provide additional active sites for the substrate, thus increasing the reaction rate even when the substrate concentration is already high.
4. Analyze the effect of pH and temperature: While changes in pH and temperature can affect enzyme activity, they do not directly address the issue of saturation. Optimal pH and temperature are important for enzyme function but do not increase the reaction rate when the enzyme is saturated.
5. Conclude that increasing enzyme concentration is the most effective way to increase the reaction rate when the enzyme is saturated with substrate, as it provides more active sites for the reaction to occur.