`Zn^(2+)` ions bound tightly to apoenzyme part of this holoenzyme

Options

A. hexokinase
B. catalase
C. carbonic anhydrase
D. pyruvic kinase

Answer

To solve the question regarding which enzyme has `Zn^(2+)` ions bound tightly to its apoenzyme part, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Apoenzyme**: This is the protein part of an enzyme that requires a cofactor to be active.
- **Cofactor**: This can be a non-protein molecule that assists in enzyme activity. It can be further classified into two categories: organic (coenzymes) and inorganic (metal ions).

2. **Identify the Holoenzyme**:
- A holoenzyme is formed when an apoenzyme binds with its cofactor. In this case, we are looking for a holoenzyme where the cofactor is a metal ion, specifically `Zn^(2+)`.

3. **Analyze the Options**:
- The options provided are:
- Hexokinase
- Catalase
- Carbonic Anhydrase
- Pyruvic Kinase

4. **Determine the Role of Zinc**:
- Zinc ions (Zn^(2+)) are known to act as cofactors for certain enzymes. They can bind tightly to the apoenzyme, which is crucial for the enzyme's activity.

5. **Identify the Correct Enzyme**:
- Among the options, **Carbonic Anhydrase** is known to be a zinc-containing enzyme. It is often referred to as a "zinc protein" because it requires zinc ions for its enzymatic function.

6. **Conclusion**:
- Since Carbonic Anhydrase is the enzyme that binds zinc ions tightly to its apoenzyme part, the correct answer is **Carbonic Anhydrase**.

### Final Answer:
The enzyme that has `Zn^(2+)` ions bound tightly to its apoenzyme part is **Carbonic Anhydrase**.

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