These components can not form holoenzyme

Options

A. Apoenzyme and Co - enzyme
B. Apoenzyme and Prosthetic group
C. Apoenzyme and Co - factor
D. Co - enzyme and Prosthetic group

Answer

To determine which components cannot form a holoenzyme, we need to understand the definition and composition of a holoenzyme.

### Step-by-Step Solution:

1. **Understanding Holoenzyme**:
- A holoenzyme is a complete, active enzyme that consists of two main components: an apoenzyme and a cofactor.
- The apoenzyme is the protein part, while the cofactor can be a non-protein part that is essential for the enzyme's activity.

2. **Components of Cofactors**:
- Cofactors can be further divided into two types:
- **Coenzymes**: These are organic molecules that assist in enzyme activity.
- **Prosthetic Groups**: These are inorganic or organic molecules that are tightly bound to the enzyme.

3. **Analyzing the Options**:
- **Option 1**: Apoenzyme + Coenzyme
- This combination includes a protein part (apoenzyme) and a non-protein part (coenzyme). This can form a holoenzyme.
- **Option 2**: Apoenzyme + Prosthetic Group
- This combination also includes a protein part (apoenzyme) and a non-protein part (prosthetic group). This can form a holoenzyme.
- **Option 3**: Apoenzyme + Cofactor
- Here, the apoenzyme (protein) is combined with a cofactor (which can be either a coenzyme or a prosthetic group). This can also form a holoenzyme.
- **Option 4**: Coenzyme + Prosthetic Group
- Both components in this option are non-protein parts. Since a holoenzyme requires at least one protein part (apoenzyme), this combination cannot form a holoenzyme.

4. **Conclusion**:
- The components that cannot form a holoenzyme are found in **Option 4: Coenzyme + Prosthetic Group**.

### Final Answer:
The components that cannot form a holoenzyme are **Coenzyme + Prosthetic Group**.