Posttranslational modifications (PTMs) encompass changes to the side chains of amino acids in certain proteins that occur after their synthesis. These diverse modifications, numbering over 400, profoundly influence various aspects of protein functions.
Vitamin K assumes a vital role in the synthesis of several proteins that are indispensable for blood clotting and bone development. It is also referred to as anti-hemorrhagic factor or phylloquinone.
During the process of blood coagulation, vitamin K plays a pivotal role in the synthesis of prothrombin and factors VII, IX, and X. It actively participates in the posttranslational modifications of these proteins, specifically by facilitating the γ-carboxylation of glutamate residues.
Vitamin K seems to serve as both a precursor and a potential enzyme in the formation of prothrombin, a product of liver metabolism.
Another protein, osteocalcin, relies on vitamin K for the production of healthy bone tissue. Vitamin K exerts its anabolic effect on bone turnover through several mechanisms, including the promotion of osteoblast differentiation, upregulation of specific genes in osteoblasts, and activation of bone-associated vitamin K-dependent proteins, which play crucial roles in the mineralization of the extracellular bone matrix.
Foods rich in this vitamin are primarily composed of vitamin K1 (with K2 accounting for only 10%). These vitamin-rich foods can be found in abundant quantities in green vegetables that are rich in chlorophyll, such as spinach, broccoli, kale, Brussels sprouts, lettuce, and parsley.
Vitamin K and posttranslational modification