Reduction of semidehydroascorbate to ascorbate Authored: D'Eustachio, P, 2007-07-05 13:27:27 Pubmed17222174 Pubmed7668255 Reactome Database ID Release 43198845 Reactome, http://www.reactome.org ReactomeREACT_11100 The reduction of cytosolic semidehydroascorbate to ascorbate is catalyzed by cytochrome B5 (CYB5A) associated with the mitochondrial outer membrane. In the course of the reaction, the heme iron of the cytochrome is oxidized (Linster and Van Schaftingen 2007; Shirabe et al. 1995). ferrous CYB5A ferric CYB5A