Question

Which of the following co-enzymes are nucleotide in nature?
(A). NAD
(B). Co-enzyme A
(C). FMN
(D). TPP
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (C) and (D) only.
• C. (B), (C) and (D) only.
• D. (A), (B) and (C) only.

Hint:

Nucleotide co-enzymes usually contain an adenosine core (like NAD, NADP, FAD, and Coenzyme A) or a phosphate-modified vitamin structure (like FMN).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Many co-enzymes contain nucleotide structures (a nitrogenous base, a ribose sugar, and phosphate groups) as part of their chemical backbone.

Step 2: Detailed Explanation:
- NAD (A): Nicotinamide Adenine Dinucleotide contains two nucleotide units: nicotinamide mononucleotide and adenosine mononucleotide linked by their phosphate groups. (Nucleotide-based)
- Co-enzyme A (B): Contains an adenosine 3'-phosphate, 5'-pyrophosphate group linked to pantothenic acid and beta-mercaptoethylamine. (Nucleotide-based)
- FMN (C): Flavin Mononucleotide consists of a riboflavin molecule phosphorylated at the 5'-position, functioning structurally and chemically as a nucleotide analog. (Nucleotide-based)
- TPP (D): Thiamine Pyrophosphate consists of a thiazole ring linked to a pyrimidine ring with a pyrophosphate group, but lacks a ribose sugar and is not classified as a nucleotide.
- Thus, (A), (B), and (C) are nucleotide co-enzymes.

Step 3: Final Answer:
The co-enzymes that are nucleotide in nature are (A), (B) and (C) only.