Determination of the warfarin inhibition constant Ki for vitamin K 2,3-epoxide reductase complex subunit-1 (VKORC1) using an in vitro DTT-driven assay

In contrast to warfarin IC50 values determined in previous studies, warfarin inhibition expressed as Ki can now be compared between studies, even when the specific DTT-driven VKOR assay conditions differ. This implies that warfarin inhibition reported for wild-type and variant VKORC1 enzymes from previous reports should be reassessed and new determinations of Ki are required to accurately report and compare in vitro warfarin inhibition results.