Role of Vitamin K in blood clotting

Vitamin K is a fat-soluble vitamin. The K is derived from German word koagulation. When the person gets a cut, whether small or large and starts to bleed, a series of reactions forms a clot that stops the flow of blood.

This cascade of reactions involves the production of a series of proteins, and ultimately the protein fibrin.

For blood to clot, fibrinogen, a soluble protein, must be converted to fibrin, an insoluble fiber network.

In this process a peptide is removed by proteolysis. Vitamin K is necessary for the maintenance normal levels of not only prothrombin (factor II) but also blood clotting factors VII, IX and X.

All these four blood clotting factors are synthesized in the liver as inactive precursors and the conversion to their active forms requires vitamin K.

Vitamin K converts the precursor protein preprothrombin to prothrombin by adding carbon dioxide to glutamic acid (an amino acid) in the protein.

This change imparts a calcium-binding capacity, which allows prothrombin to be changed to thrombin.
Role of Vitamin K in blood clotting