vitamin K epoxide -> vitamin K hydroquinone Authored: D'Eustachio, P, 2005-03-17 16:24:57 EC Number: 1.1.4.1 Edited: D'Eustachio, P, 0000-00-00 00:00:00 Pubmed14765176 Pubmed14765194 Pubmed14765195 Pubmed3932474 Reactome Database ID Release 43159790 Reactome, http://www.reactome.org ReactomeREACT_950 The regeneration of reduced vitamin K (vitamin K hydroquinone) from vitamin K epoxide is catalyzed by vitamin K epoxide reductase (VKORC1) (Sadler 2004). This enzyme is the target of the anticoagulant drug warfarin. Two important features of this reaction remain unclear. First, dithiothreitol functions efficiently as a reductant in vitro (Wallin and Martin 1985), but the in vivo reductant remains unknown. Second, while people homozygous for mutations in VKORC1 protein lack epoxide reductase activity (Rost et al. 2004) and cultured insect cells transfected with the cloned human VKORC1 gene express vitamin K epoxide reductase activity (Li et al. 2004), the possibility that the active form of the enzyme is a complex with other proteins cannot be formally excluded. has a Stoichiometric coefficient of 2