Which is best evidence for Lock and key theory (Template theroy)?

Options

A. Competitve inhibition
B. Feed back inhibition
C. Allosteric competition
D. Non-competitive inhibition

Answer

To determine the best evidence for the Lock and Key theory (Template theory), we need to analyze the provided options in relation to the theory itself.

### Step-by-Step Solution:

1. **Understand the Lock and Key Theory**:
- The Lock and Key theory suggests that enzymes have a specific shape (the lock) that only allows a specific substrate (the key) to bind to it. This forms an enzyme-substrate complex, leading to the formation of products.

2. **Examine the Options**:
- **Competitive Inhibition**: In this scenario, an inhibitor that resembles the substrate competes with the substrate for binding to the active site of the enzyme. This is similar to how a key that fits a lock can prevent another key from entering.
- **Feedback Inhibition**: This is a regulatory mechanism where the end product of a metabolic pathway inhibits an earlier step in the pathway. It does not directly demonstrate the specificity of enzyme-substrate binding.
- **Allosteric Competition**: This involves the binding of an effector molecule at a site other than the active site, which alters the enzyme's activity. This does not directly relate to the lock and key specificity.
- **Non-Competitive Inhibition**: Here, an inhibitor binds to an enzyme regardless of whether the substrate is bound or not. This does not illustrate the specific binding characteristic of the lock and key model.

3. **Identify the Best Evidence**:
- Among the options, **Competitive Inhibition** is the best evidence for the Lock and Key theory. This is because it directly involves a substrate (or a similar molecule) competing for the active site of the enzyme, demonstrating the specificity and shape compatibility that the theory describes.

4. **Conclusion**:
- Therefore, the best evidence for the Lock and Key theory is **Competitive Inhibition**.