Why is the induced-fit model a more likely model than the lock-and-key model?

Verified step by step guidance

1. Understand the two models: The lock-and-key model suggests that the enzyme's active site is a perfect fit for the substrate, like a key fitting into a lock. The induced-fit model proposes that the enzyme's active site is flexible and can adjust its shape to fit the substrate more snugly.
2. Consider enzyme flexibility: Enzymes are not rigid structures. The induced-fit model accounts for the dynamic nature of enzymes, where the active site can change shape to better accommodate the substrate.
3. Evaluate substrate specificity: The induced-fit model explains how enzymes can be highly specific for their substrates, as the active site can mold itself around the substrate, enhancing the enzyme's ability to catalyze the reaction.
4. Analyze experimental evidence: Many studies have shown that enzymes undergo conformational changes upon substrate binding, supporting the induced-fit model over the lock-and-key model.
5. Reflect on catalytic efficiency: The induced-fit model can explain how enzymes lower activation energy more effectively by stabilizing the transition state, which is not as easily explained by the lock-and-key model.

Key Concepts

Induced-Fit Model

The induced-fit model describes how an enzyme changes shape upon substrate binding, allowing for a more precise fit. This flexibility enhances the enzyme's ability to catalyze reactions, as the active site adapts to the substrate's shape, improving the interaction and efficiency of the reaction.

Lock-and-Key Model

The lock-and-key model suggests that enzymes and substrates fit together perfectly, like a key in a lock. While this model illustrates the specificity of enzyme-substrate interactions, it does not account for the dynamic nature of enzymes and their ability to undergo conformational changes during catalysis.

Enzyme Catalysis

Enzyme catalysis refers to the process by which enzymes accelerate chemical reactions. Understanding this concept is crucial for evaluating the effectiveness of different models, as it highlights the importance of enzyme structure and flexibility in facilitating substrate conversion into products.