As a result of posttranslative modifications some proteins taking part in blood coagulation, particularly prothrombin, become capable of calcium binding. The following vitamin takes part in this process:

Answer options

1. C
2. Bi
3. B2
4. A
5. K

Explanation

Gamma-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-carboxyglutamic acid, the gamma -proton on glutamic acid is abstracted, and CO2 is subsequently added. This process is called carboxylation of glutamine acid.