Which one of the following statements is correct, with reference to enzymes ?

Options

A. Holoenzyme - Apoenzyme + Coenzyme
B. Coenzyme = Apoenzyme + Holoenzyme
C. Holoenzyme = Coenzyme + Co-factor
D. Apoenzyme = Holoenzyme + Coenzyme

Answer

To determine which statement is correct with reference to enzymes, let's analyze the definitions and relationships between holo-enzyme, apo-enzyme, co-enzyme, and co-factor.

### Step-by-Step Solution:

1. **Understanding Enzymes**:
- Enzymes are biological catalysts that speed up biochemical reactions. They are primarily proteins.

2. **Defining Holo-enzyme**:
- A holo-enzyme is the active form of an enzyme that consists of two components: the apo-enzyme and the co-factor (which can be a co-enzyme or a metal ion).

3. **Defining Apo-enzyme**:
- The apo-enzyme is the protein part of the enzyme that is inactive on its own. It requires a co-factor or co-enzyme to become active.

4. **Defining Co-enzyme**:
- A co-enzyme is a non-protein organic molecule that assists the apo-enzyme in becoming active. It is necessary for the enzyme's activity.

5. **Analyzing the Statements**:
- **Statement 1**: Holo-enzyme = Apo-enzyme + Co-enzyme (Correct)
- **Statement 2**: Co-enzyme = Apo-enzyme + Holo-enzyme (Incorrect)
- **Statement 3**: Holo-enzyme = Co-enzyme + Co-factor (Incorrect)
- **Statement 4**: Apo-enzyme = Holo-enzyme + Co-enzyme (Incorrect)

6. **Conclusion**:
- The correct statement is that the holo-enzyme is equal to the apo-enzyme plus the co-enzyme. Therefore, the answer is **Statement 1**.