VKORC1 reduces vitamin K epoxide to MK4 (vitamin K hydroquinone)

Stable Identifier
R-HSA-159790
Type
Reaction [transition]
Species
Homo sapiens
Compartment
Synonyms
MK4 epoxide => MK4
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The regeneration of reduced vitamin K (vitamin K hydroquinone) from vitamin K epoxide is catalyzed by vitamin K epoxide reductase (VKORC1) (Sadler 2004). Two important features of this reaction remain unclear. First, dithiothreitol functions efficiently as a reductant in vitro (Wallin & 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.

Literature References
PubMed ID Title Journal Year
14765194 Mutations in VKORC1 cause warfarin resistance and multiple coagulation factor deficiency type 2

Rost, S, Fregin, A, Ivaskevicius, V, Conzelmann, E, Hortnagel, K, Pelz, HJ, Lappegard, K, Seifried, E, Scharrer, I, Tuddenham, EG, Müller, CR, Strom, TM, Oldenburg, J

Nature 2004
14765195 Identification of the gene for vitamin K epoxide reductase

Li, T, Chang, CY, Jin, DY, Lin, PJ, Khvorova, A, Stafford, DW

Nature 2004
Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
vitamin-K-epoxide reductase (warfarin-sensitive) activity of VKORC1 dimer [endoplasmic reticulum membrane]
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Activity
This event is regulated
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