NADPH, an acronym for Nicotinamide Adenine Dinucleotide Phosphate, is a coenzyme that plays a crucial role in various biochemical reactions in living organisms. It is a reduced form of NADP+ that carries high-energy electrons and hydrogen atoms necessary for numerous biological processes, particularly in anabolic reactions.
NADPH is primarily involved in anabolic pathways, serving as a reducing agent by supplying the necessary electrons and hydrogen for biosynthetic reactions. It is an essential cofactor in several key metabolic pathways, including fatty acid synthesis, cholesterol biosynthesis, and nucleotide synthesis. Furthermore, NADPH is vital for maintaining the optimal levels of antioxidants, such as glutathione, which helps protect cells from oxidative damage caused by reactive oxygen species.
The production of NADPH occurs primarily through the pentose phosphate pathway (PPP) or the oxidative branch of glucose metabolism. This pathway involves the enzymatic conversion of glucose-6-phosphate into ribulose-5-phosphate, generating NADPH and carbon dioxide as byproducts.
NADPH also plays a critical role in supporting various other cellular processes, including the detoxification of drugs and foreign compounds by the cytochrome P450 system in the liver, as well as the immune system's defense mechanisms, such as the respiratory burst in phagocytes.
In summary, NADPH is a vital coenzyme that acts as a reducing agent, providing high-energy electrons and hydrogen for anabolic reactions, maintaining antioxidant defenses, supporting detoxification processes, and facilitating immune responses.
