Organic compounds that are tightly bound to apoenzyme is

Options

A. Prosthetic group
B. Apoenzyme
C. Metal ions
D. Co-enzymes

Answer

To answer the question "Organic compounds that are tightly bound to apoenzyme is," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Enzymes**:
- Enzymes are biological catalysts that speed up chemical reactions. They consist of two main parts:
- **Apoenzyme**: This is the protein part of the enzyme.
- **Cofactor**: This is a non-protein part that is necessary for the enzyme's activity.

2. **Identify the Types of Cofactors**:
- Cofactors can be further classified into two categories:
- **Inorganic cofactors**: These are usually metal ions (like Zn²⁺, Mg²⁺).
- **Organic cofactors**: These are often referred to as coenzymes and prosthetic groups.

3. **Differentiate Between Coenzymes and Prosthetic Groups**:
- **Coenzymes**: These are organic molecules that are loosely bound to the enzyme. They can detach and reattach during the reaction process.
- **Prosthetic Groups**: These are also organic molecules, but they are tightly bound to the enzyme. They remain attached throughout the enzyme's function.

4. **Determine the Correct Answer**:
- Since the question specifically asks for organic compounds that are tightly bound to the apoenzyme, the correct answer is the **prosthetic group**.

### Final Answer:
The organic compounds that are tightly bound to the apoenzyme are called **prosthetic groups**.

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