Reduction of dehydroascorbate to ascorbate ferric CYB5A + NADH + H+ => ferrous CYPB5A + NAD+ Reduction of semidehydroascorbate to ascorbate Ascorbate transport across the plasma membrane Dehydroascorbate transport across the plasma membrane PathwayStep2333 PathwayStep2329 PathwayStep2330 PathwayStep2332 PathwayStep2331 Vitamin C (ascorbate) metabolism Authored: Jassal, B, 2007-04-24 08:38:46 GENE ONTOLOGYGO:0019852 Pubmed17222174 Reactome Database ID Release 43196836 Reactome, http://www.reactome.org ReactomeREACT_11202 Vitamin C (ascorbate) is an antioxidant and a cofactor in reactions catalyzed by Cu+-dependent monooxygenases and Fe++-dependent dioxygenases. Many mammals can synthesize ascorbate de novo; humans and other primates cannot due to an evolutionarily recent mutation in the gene catalyzing the last step of the biosynthetic pathway. Reactions annotated here mediate the uptake of ascorbate and its fully oxidized form, dehydroascorbate (DHA) by cells, and the reduction of DHA and monodehydroascorbate to regenerate ascorbate (Linster and Van Schaftingen 2007).