6-Phosphogluconate Dehydrogenase (PGD)

PGD is a cytosolic enzyme that catalyzes the oxidative decarboxylation of 6-phosphogluconate to ribulose 5-phosphate and CO₂, coupled with reduction of NADP to NADPH (UniProt: P52209). It is a key component of the pentose phosphate pathway, which generates reducing equivalents required for biosynthetic reactions and antioxidant defense.

The protein functions in central carbohydrate metabolism and oxidative stress management. No disease associations are documented in UniProt. PGD is expressed broadly across tissues supporting high metabolic demand.

PGD shows elevated levels in Alzheimer's Disease brain tissue. In human post-mortem AD brain compared to age-matched controls (Chaparral AD proteomics), PGD is upregulated with a mean log2 fold-change of 0.44 across two subcellular fractions (P2, P3) detected by quantitative mass spectrometry. This increase may reflect compensatory enhancement of pentose phosphate pathway activity or antioxidant responses to oxidative stress in AD pathology.