Figure 1.

The currently known pathways for AsA biosynthesis and recycling in higher plants. Abbreviations: Phosphoglucoisomerase, PGI; mannose-6-phosphate isomerase, PMI; phosphomannomutase, PMM; GDP-mannose pryophosphorylase, GMP; GDP-mannose-3′,5′-epimerase, GME; GDP-L-galactose phosphorylase, GGP; L-galactose-l-phosphate phosphatase, GPP; L-galactose dehydrogenase, GalDH; L-galactono-1,4-lactone dehydrogenase, GalLDH; myo-inositol oxygenase, MIOX; D-galacturonate reductase, GalUR; ascorbate peroxidase, APX; monodehydroascorbate reductase, MDHAR; dehydroascorbate reductase, DHAR; ascorbate oxidase, AO.