Vitamin K Epoxide Reductase Complex Subunit 1 (VKORC1)

Vitamin K is essential for blood clotting but must be enzymatically activated. This enzymatically activated form of vitamin K is a reduced form required for the carboxylation of glutamic acid residues in some blood-clotting proteins.

VKORC1 is responsible for reducing vitamin K 2,3-epoxide to the enzymatically activated form. Fatal bleeding can be caused by vitamin K deficiency and by the vitamin K antagonist warfarin, and it is the product of this gene that is sensitive to warfarin. In humans, mutations in this gene can be associated with deficiencies in vitamin-K-dependent clotting factors and, in humans and rats, with warfarin resistance. Two pseudogenes have been identified on chromosome 1 and the X chromosome. Two alternatively spliced transcripts encoding different isoforms have been described.