Glucose-6-phosphate dehydrogenase (G6PD)

Glucose-6-phosphate dehydrogenase (G6PD) is a critical enzyme that catalyzes the first and rate-limiting step of the pentose phosphate pathway (PPP), converting glucose-6-phosphate into 6-phosphoglucono-δ-lactone while reducing NADP+ to NADPH. It is essential for producing ribose-5-phosphate, a precursor for nucleotide synthesis, and generating NADPH, which is vital for reductive biosynthesis and antioxidant defense. In red blood cells, G6PD-derived NADPH maintains glutathione in its reduced form, protecting cells from oxidative damage by neutralizing reactive oxygen species (ROS). G6PD deficiency can lead to increased susceptibility to hemolytic anemia under oxidative stress.