Which coagulation family relies on vitamin K for its synthesis?

The prothrombin family relies on vitamin K for its synthesis. This family includes critical coagulation factors such as prothrombin (factor II), factors VII, IX, and X, all of which require vitamin K for their post-translational modifications. These modifications involve the gamma-carboxylation of certain glutamic acid residues, which is essential for the factors to bind calcium ions. This calcium binding is crucial for the proper functioning of these factors in the coagulation cascade.

The vitamin K-dependent modification enhances the ability of these factors to participate in the coagulation process, specifically in the extrinsic and common pathways of coagulation. Without sufficient vitamin K, the factors would be unable to function correctly, leading to impaired hemostasis and an increased risk of bleeding.

Other coagulation factors such as those in the fibrinogen family or factors in the intrinsic pathway do not depend on vitamin K for their synthesis or activation, which differentiates the prothrombin family as uniquely reliant on this important vitamin.