Which of the following best describes the induced fit model of enzyme-substrate interaction?

• A. The substrate must fit perfectly into a rigid, pre-formed active site of the enzyme.
• B. The enzyme and substrate form a covalent bond that permanently alters the enzyme.
• C. The enzyme changes its shape slightly to better fit the substrate upon binding.
• D. The enzyme is denatured by the substrate before catalysis can occur.

Answer: (C)

Verified step by step guidance

1. Understand the concept of enzyme-substrate interaction: Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy. The active site of an enzyme is where the substrate binds, and this interaction is crucial for catalysis.
2. Learn about the induced fit model: Unlike the lock-and-key model, which suggests a rigid active site, the induced fit model proposes that the enzyme's active site is flexible and can adjust its shape to better accommodate the substrate upon binding.
3. Analyze the options provided: Evaluate each statement to determine which aligns with the induced fit model. For example, the statement 'The substrate must fit perfectly into a rigid, pre-formed active site of the enzyme' describes the lock-and-key model, not the induced fit model.
4. Focus on the correct description: The induced fit model emphasizes that the enzyme changes its shape slightly to better fit the substrate upon binding. This dynamic adjustment enhances the enzyme's ability to catalyze the reaction.
5. Eliminate incorrect options: Discard statements that suggest permanent alteration of the enzyme, denaturation, or rigid active sites, as these do not align with the induced fit model. Select the statement that accurately describes the enzyme's flexibility and adaptability during substrate binding.