Warfarin inhibits synthesis of vit K-dependent coagulation factors II, VII, IX, and X as well as the anticoagulant protein C and its cofactor protein S. These clotting factors are biologically activated by the addition of carboxyl groups to key glutamic acid residues w/in the proteins' structure. Warfarin competitively inhibits the C1 subunit of the multi-unit vit K epoxide reductase (VKORC1) enzyme complex, thus depleting functional vit K reserves and hence reduces synthesis of active clotting factors.