Holoenzyme is composed of :

Options

A. Non - protein and apoenzyme
B. protein and apoenzyme
C. Enyme , protein and coenzyme
D. Enzyme , non - protein and coenzyme

Answer

### Step-by-Step Solution:

1. **Understanding Holoenzyme**:
- A holoenzyme is a complete and active enzyme that consists of two main components: an apoenzyme and a cofactor.

2. **Defining Apoenzyme**:
- The apoenzyme is the protein part of the enzyme. It is inactive on its own and requires a cofactor to become active.

3. **Identifying Cofactor**:
- The cofactor is a non-protein component that assists in the enzyme's activity. It can be a metal ion or an organic molecule.

4. **Types of Cofactors**:
- Cofactors can be metal ions (like Zn²⁺ and Fe²⁺) or organic molecules (often referred to as coenzymes).

5. **Formation of Holoenzyme**:
- When the apoenzyme (the protein part) combines with the cofactor (the non-protein part), it forms the holoenzyme, which is the active form of the enzyme.

6. **Conclusion**:
- Therefore, the holoenzyme is composed of an apoenzyme and a cofactor.

### Final Answer:
Holoenzyme is composed of an apoenzyme and a cofactor.