Vitamin K is necessary for normal blood coagulation. Which of the following processes of hemostasis is dependent on the activity of this vitamin?

Question

Quizplus · Accepted Answer

Vitamin K is essential for the carboxylation of glutamic acid residues on certain coagulation factors, which is necessary for their activity in the coagulation cascade.  The major function of the K vitamins is in the maintenance of normal levels of the blood-clotting proteins, factors II, VII, IX, X, and protein C and protein S, which are synthesized in the liver as inactive precursor proteins. Conversion from inactive to active clotting factor requires a posttranslational modification of specific glutamate (E) residues. This modification is a carboxylation and the enzyme responsible requires vitamin K as a cofactor. The resultant modified E residues are g-carboxyglutamate (gla).

Vitamin K Is Necessary for Normal Blood Coagulation