Difference between NADH and NADPH

NADH (Nicotinamide Adenine Dinucleotide) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate) are coenzymes involved in cellular metabolism. Although both are derived from the same precursor molecule, they differ in their functions and roles in the metabolic processes.

Structure and Biosynthesis
- NADH and NADPH are nucleotide derivatives and are synthesized from nicotinamide, ribose, and phosphate groups.
- Both molecules are composed of two nucleotides joined by a phosphate group, with an adenine base and a nicotinamide group.
- NADH is synthesized from NAD+ by the addition of two electrons and a hydrogen ion to the nicotinamide ring.
- NADPH is synthesized from NADP+ by the addition of a phosphate group and two electrons and a hydrogen ion to the nicotinamide ring.

Function
- NADH is involved in catabolic processes such as glycolysis, Krebs cycle, and oxidative phosphorylation. It acts as an electron carrier, donating electrons to the electron transport chain to produce ATP.
- NADPH is involved in anabolic processes such as fatty acid and nucleic acid synthesis. It acts as a reducing agent, providing electrons for biosynthetic reactions.

Role in Redox Reactions
- NADH is a powerful reducing agent and donates electrons to other molecules. It is oxidized to NAD+ in the process.
- NADPH is a reducing agent and donates electrons to other molecules. It is oxidized to NADP+ in the process.

Distribution
- NADH is found in all living cells and is involved in energy metabolism.
- NADPH is found primarily in the cytoplasm of cells and is involved in biosynthetic reactions.

In conclusion, NADH and NADPH are coenzymes involved in cellular metabolism. They differ in their functions, roles in metabolic processes, and distribution in cells. While NADH is involved in catabolic processes, NADPH is involved in anabolic processes.