Yes, NAD (nicotinamide adenine dinucleotide) is indeed a coenzyme.
NAD is a crucial coenzyme found in all living cells. It plays a pivotal role in a wide range of metabolic processes. These processes include:
- Glycolysis: NAD+ acts as an oxidizing agent, accepting electrons during the oxidation of glyceraldehyde-3-phosphate.
- β-oxidation: NAD+ accepts electrons during the oxidation of fatty acids.
- Oxidative Phosphorylation: NADH donates electrons to the electron transport chain, which is essential for ATP production.
NAD exists in two forms: NAD+ (the oxidized form) and NADH (the reduced form). These forms are interconverted during redox reactions, where NAD+ accepts electrons and is reduced to NADH, or NADH donates electrons and is oxidized to NAD+. This cycling between NAD+ and NADH is critical for energy transfer and cellular metabolism. The reference you provided specifically mentions this, highlighting its importance as a regulator of these pathways.
Therefore, based on its function in facilitating enzyme-catalyzed reactions in metabolism, NAD is definitively classified as a coenzyme.
