Question

Which of the following is not a coenzyme?

• A. NAD
• B. NADP
• C. FAD
• D. ATP

Answer 1

The correct option is D ATP

Many enzymes consists of a protein and non-protein component, they are called as holoenzymes. The protein component of a holoenzyme is called as apoenzyme and the non-protein component may be inorganic ions such as Mg${}^{2+}$ and Mn${}^{2+}$. They are tightly attached to apoenzyme, they are called as activators. The non-protein components may be organic substances such as NAD+, NADP+ and FAD+. They are loosely attached to the apoenzyme. They are called coenzyme or cofactors.