NADPHtuotanto

NADPHtuotanto refers to the biological process of producing NADPH (nicotinamide adenine dinucleotide phosphate hydrogen), a vital coenzyme involved in various cellular metabolic pathways. NADPH serves primarily as a reducing agent, providing the necessary electrons for biosynthetic reactions and antioxidant defense mechanisms.

In cellular metabolism, NADPH is generated predominantly through the pentose phosphate pathway (PPP), also known as the hexose monophosphate shunt. This pathway occurs alongside glycolysis and is active in various cell types, especially in tissues with high biosynthetic activity, such as the liver, adipose tissue, and rapidly proliferating cells.

The primary enzyme responsible for NADPH production in the PPP is glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the first step, converting glucose-6-phosphate into 6-phosphoglucono-δ-lactone while reducing NADP+ to NADPH. Another significant contributor is the enzyme 6-phosphogluconate dehydrogenase, which catalyzes an oxidative decarboxylation step, further generating NADPH.

Apart from the PPP, NADPH can also be produced through other enzymatic reactions, including malic enzyme-mediated decarboxylation of malate, and isocitrate dehydrogenase activity in the cytosol, particularly in certain tissues.

NADPH is essential for reductive biosynthesis, such as fatty acid and cholesterol synthesis, and for maintaining the reduced form of glutathione, which protects cells from oxidative stress. Proper NADPH production is critical for cellular health, and deficiencies in NADPH-generating enzymes can lead to metabolic disorders and increased vulnerability to oxidative damage.