Fig. 1
From: Cell-based and cell-free biocatalysis for the production of d-glucaric acid
Glucuronic acid (GlcA) pathway and glucaric acid (GA) biosynthesis in natural cells. Glucose-6-phosphate (G6P) formed from glucose is isomerized into glucose-1-phosphate (G1P) by phosphoglucomutase, and then G1P reacts with uridine triphosphate (UTP) [catalyzed by uridine 5′‑diphosphate-glucose (UDP-Glc) pyrophosphorylase] to form UDP-Glc, which is then oxidized in a two-step process by an NAD+-dependent UDP-Glc dehydrogenase to form UDP-GlcA. UDP-GlcA is hydrolyzed to form UDP and d-GlcA. The latter then undergoes a three-step conversion reaction through the intermediates d-glucuronic-γ-lactone and d-glucaro-γ-lactone to form GA [9]. However, natural GA is found only at pmol or nmol concentrations in plant and mammalian cells, too low for it to be obtained directly [3]