Dioxygen transfer during vitamin K dependent carboxylase catalysis

The vitamin K dependent carboxylase of liver microsomes is involved in the posttranslational modification of certain serine protease zymogens which are critical components of the blood clotting cascade. During coupled carboxylation/oxygenation this carboxylase converts glutamate residues, dihydrovitamin K, CO 2 , and O 2 to a γ-carboxyglutamyl (Gla) residue, vitamin K (2R,3S)-epoxide, and H 2 O with a stoichiometry of 1:1 for all substrates and products