The protein portion of an enzyme is called:

Question

The protein portion of an enzyme is called:

1. A. Cofactor
2. B. Coenzyme
3. C. Apoenzyme (Correct answer)
4. D. Prosthetic group

Correct Answer

Option C — Apoenzyme

Detailed Solution & Explanation

The correct answer is Apoenzyme.

Key Points

• When a non-protein cofactor is bound to an enzyme, the protein portion is called the apoenzyme.
• Cofactors are the non-protein parts — they include prosthetic groups (tightly bound), coenzymes (transiently bound organic molecules) and metal ions.