An organic substance which is a non-protein part of an enzyme is known as

Options

A. holoenzyrne
B. apoenzyme
C. isoenzyme
D. coenzyme

Explanation

To solve the question "An organic substance which is a non-protein part of an enzyme is known as", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Enzymes**: Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are primarily made up of proteins.

2. **Identifying Parts of Enzymes**: Enzymes can be classified into two main parts:
- **Apoenzyme**: This is the protein part of the enzyme.
- **Cofactor**: This is the non-protein part of the enzyme, which is essential for its activity.

3. **Types of Cofactors**: Cofactors can be further classified into:
- **Inorganic Cofactors**: These are usually metal ions (like zinc or magnesium).
- **Organic Cofactors**: These are often referred to as coenzymes. Examples include vitamins that assist in enzyme function.

4. **Identifying the Correct Term**: The question specifically asks for an organic substance that is a non-protein part of an enzyme. This is best described as a **coenzyme**.

5. **Conclusion**: Therefore, the answer to the question is that the organic substance which is a non-protein part of an enzyme is known as a **coenzyme**.

### Final Answer:
The correct answer is **coenzyme**.

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