6-phosphoglucono-δ-lactone is a biochemical compound that plays a crucial role in the pentose phosphate pathway, a metabolic pathway important for cellular processes. It is formed from glucose-6-phosphate through the action of the enzyme glucose-6-phosphate dehydrogenase. This compound is a lactone, which means it is a cyclic ester, and it serves as an intermediate in the production of ribulose-5-phosphate. In addition to its role in metabolism, 6-phosphoglucono-δ-lactone is involved in the generation of reducing equivalents in the form of NADPH, which is essential for biosynthetic reactions and maintaining cellular redox balance. Its conversion to other metabolites helps provide the necessary components for nucleotide synthesis and fatty acid production.