Figure 1.

The ascorbate metabolic network in plants and animals. The D‐mannose/L‐galactose route, the L‐gulose shunt, the D‐galacturonate route, and the myo‐inositol pathway. Enzymes: 1 phosphoglucose isomerase: 2 phosphomannose isomerase; 3 phosphomannose mutase; 4 GDP‐mannose pyrophosphorylase; 5 GDP‐mannose, 3′5′ epimerase; 6 GDP‐galactose phosphorylase; 7 L‐galactose‐1‐P‐phosphatase; 8 L‐galactose dehydrogenase; 9 L‐galactono‐1,4‐lactone dehydrogenase; 10 galacturonate reductase; 11 aldonolactonase; 12 myo‐inositol 1‐P phosphatase; 13 myo‐inositol oxygenase; 14 UDP‐glucose pyrophosphorylase; 15 UDP‐glucose dehydrogenase; 16 UDP‐glucuronate pyrophosphorylase; 17 glucuronate 1‐kinase; 18 glucuronate reductase; 19 glucuronolactonase; 20 L‐gulono‐1,4‐lactone oxidase; 21 monodehydroascorbate reductase; 22 dehydroascorbate reductase. Broken arrows indicate multiple reactions