Plasmic factors of blood coagulation are exposed to post-translational modification with the participation of vitamin K. It is necessary as a cofactor in the enzyme system of γ-carboxylation of protein factors of blood coagulation due to the increased affinity of their molecules with calcium ions. What amino acid is carboxylated in these proteins?

Answer options

1. Serine
2. Arginine
3. Phenylalanine
4. Valine
5. Glutamic

Explanation

γ-Carboxyglutamic acid is a calcium-binding amino acid and is required for the function of vitamin K-dependent proteins. In the blood coagulation cascade, vitamin K is required to introduce gamma-carboxylation of clotting factors II, VII, IX, X, and protein Z. In the biosynthesis of gamma-carboxylation acid, the gamma -proton on glutamic acid is abstracted, and CO2 is subsequently added. This process is called carboxylation of glutamine acid.