The main vitamin essential for the synthesis of prothrombin is?

Vitamin K plays a crucial role in the synthesis of prothrombin, which is a vital protein in the blood coagulation process. Prothrombin is produced in the liver, and its synthesis requires vitamin K as a cofactor. Without sufficient vitamin K, the body cannot effectively produce prothrombin, leading to impaired blood clotting and increased risk of hemorrhage.

Vitamin K, specifically in its K1 (phylloquinone) and K2 (menaquinone) forms, is essential for the post-translational modification of certain proteins required for blood clotting, including prothrombin. This modification involves the addition of carboxylic acid groups to specific glutamate residues, allowing these proteins to bind calcium ions, which is necessary for their biological activity in the clotting cascade.

While other vitamins like A, C, and D have their own important roles in the body—such as vision, collagen synthesis, and calcium absorption, respectively—they are not directly involved in the synthesis of prothrombin or the blood coagulation process. Thus, vitamin K is the key nutrient required for this specific biological function.