Which is Vitamin K dependent clotting factor?: (A) Factor VII, (B) Factor I, (C) Factor XI, (D) Factor XII
Answer is A. Ans is 'a' i.e. Factor VII Vitamin K serves as an essential cofactor for an enzyme carboxylase that catalyzes carboxylation of glutamic acid residues on vitamin K-dependent proteins. The key vitamin K-dependent proteins include:Coagulation proteins: factors II (prothrombin), VII, IX and XAnticoagulation proteins: proteins C, S and ZOthers: bone proteins osteocalcin and matrix-Gla protein, and certain ribosomal proteinsThese proteins have in common the requirement to be post-translationally modified by carboxylation of glutamic acid residues (forming gamma-carboxyglutamic acid) in order to become biologically active.