6fosfoglukonolaktonas

6-phosphoglucono-δ-lactone, commonly referred to by its transliterated name 6fosfoglukonolaktonas in some languages, is an intermediate in the pentose phosphate pathway (PPP). It is formed when glucose-6-phosphate is oxidized by glucose-6-phosphate dehydrogenase (G6PD), a reaction that also generates NADPH. The product of this oxidation is 6-phosphoglucono-δ-lactone, a phosphorylated lactone that subsequently undergoes hydrolysis.

The hydrolysis of 6-phosphoglucono-δ-lactone to 6-phosphogluconate is catalyzed by the enzyme 6-phosphogluconolactonase. The resulting 6-phosphogluconate then continues through the oxidative branch of the PPP, where it is decarboxylated to ribulose-5-phosphate with the production of additional NADPH and carbon dioxide. Ribulose-5-phosphate can be isomerized or epimerized to ribose-5-phosphate, providing precursors for nucleotide synthesis, while NADPH produced in these steps powers reductive biosynthesis and helps maintain cellular redox balance.

Chemically, 6-phosphoglucono-δ-lactone is a lactone form of 6-phosphogluconic acid, containing a phosphate group and a cyclic ester derived from a carbohydrate. It is a transient metabolite found in many organisms that utilize the PPP, including bacteria and eukaryotes.

Overall, 6-phosphoglucono-δ-lactone serves as a key transitional intermediate linking the initial oxidation of glucose-6-phosphate to the production of NADPH and ribose-5-phosphate, essential for anabolic reactions and oxidative stress defense.