Question

Deficiency of Vitamin K will make blood clotting difficult because it is essential for

• A. Change of thromboplastin to thrombin
• B. Platelet
• C. Prothrombin synthesis
• D. Fibrinogen synthesis

Answer 1

The correct option is C Prothrombin synthesis

Vitamin K serves as an essential cofactor for a carboxylase that catalyzes carboxylation of glutamic acid residues on vitamin K-dependent proteins. The carboxylation of the proteins results in the formation of prothrombin. The key vitamin K-dependent proteins includes coagulation proteins like factors II (prothrombin), VII, IX and X; anticoagulation proteins like proteins C, S and Z; other bone proteins osteocalcin and matrix-Gla protein, and certain ribosomal proteins. The coagulation proteins are activated by vitamin K and hence, the process of blood clotting is initiated by vitamin K. Deficiency of this vitamin may result in no blood clotting.

Thus, the correct answer is option C.