Non-protein part of enzyme is called

Options

A. Prosthetic group
B. Active site
C. Cofactor
D. Catalytic agent.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the non-protein part of an enzyme. Enzymes are biological catalysts that speed up chemical reactions in living organisms.

2. **Analyzing the Options**:
- **Option A: Prosthetic Group**: This is a non-amino acid component that is covalently linked to a protein. While it is a non-protein part, it is specifically a part of the structure of conjugated proteins and is not the general term for all non-protein components of enzymes.
- **Option B: Active Site**: The active site is the part of the enzyme where the substrate binds and undergoes a chemical reaction. It consists of amino acid residues, making it a protein part, not a non-protein part.
- **Option C: Cofactor**: A cofactor is a non-protein part of an enzyme that can be a metal ion or an organic molecule (coenzyme). This option directly answers the question.
- **Option D: Catalytic Agent**: This term refers to substances that increase the rate of a chemical reaction but does not specifically denote a non-protein part of an enzyme.

3. **Selecting the Correct Answer**: Based on the analysis, the correct answer is **Cofactor** (Option C), as it is the non-protein part of an enzyme.

4. **Conclusion**: The non-protein part of an enzyme is called a cofactor.

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