An organic substance bound to an enzyme and essential for its activity is called

Options

A. aponezyme
B. isoenzyme
C. conenzyme
D. holoennzyme

Answer

To solve the question, "An organic substance bound to an enzyme and essential for its activity is called," let's break it down step by step:

### Step 1: Understand the Components of Enzymes
Enzymes are biological catalysts that speed up chemical reactions in the body. They are usually proteins and can be composed of different parts.

### Step 2: Identify the Types of Enzyme Components
Enzymes can exist in two forms:
- **Apoenzyme**: This is the inactive form of the enzyme, which requires additional components to become active.
- **Holoenzyme**: This is the active form of the enzyme, which is formed when the apoenzyme combines with additional components.

### Step 3: Distinguish Between Organic and Inorganic Components
The additional components that bind to the apoenzyme can be:
- **Cofactors**: These are inorganic molecules (like metal ions).
- **Coenzymes**: These are organic molecules that bind to the enzyme and are essential for its activity.

### Step 4: Answer the Question
The question specifically asks for an organic substance that is bound to an enzyme and is essential for its activity. Based on the definitions:
- The correct answer is **coenzyme**.

### Final Answer
Thus, the organic substance bound to an enzyme and essential for its activity is called a **coenzyme**.

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