6fosfoglukonatdehydrogenas

6-Phosphogluconate is a phosphorylated sugar acid that serves as an intermediate in glucose metabolism, notably within the pentose phosphate pathway (PPP) and, in some organisms, the Entner-Doudoroff pathway. In the PPP, the oxidative phase begins with the oxidation of glucose-6-phosphate to 6-phosphogluconolactone by glucose-6-phosphate dehydrogenase, followed by lactonase-catalyzed hydrolysis to 6-phosphogluconate. This metabolite then undergoes oxidative decarboxylation by 6-phosphogluconate dehydrogenase to ribulose-5-phosphate, producing CO2 and NADPH. The ribulose-5-phosphate can be isomerized or epimerized to ribose-5-phosphate or xylulose-5-phosphate, feeding nucleotide synthesis and carbon rearrangement in the non-oxidative PPP.

In several bacteria, 6-phosphogluconate is diverted from the PPP to the Entner-Doudoroff pathway, where it is dehydrated to 2-keto-3-deoxy-6-phosphogluconate and then cleaved by KDPG aldolase into pyruvate and glyceraldehyde-3-phosphate, providing an alternate route for glucose catabolism.

Chemical properties: 6-phosphogluconate is a phosphorylated aldonic acid derivative; it carries a phosphate group at carbon 6 and bears multiple negative charges at physiological pH, enabling interactions with various enzymes in central metabolism.

Overall, 6-phosphogluconate is a key branching point that links energy production, reductive biosynthesis via NADPH, and nucleotide precursor generation across diverse organisms.