Vitamin K Effects on Some Processes in the Human Body
Regina Budrionienė
Summary
This article presents data of chemical structure of vitamin K, and the sources of this vitamin as well as the metabolism and function of vitamin K. It is well known that vitamin K is important for blood clotting process participating in reduction of the process of glutamic acid carboxylation. This is important for some blood coagulation factors (II, VII, IX and X). As a reducing agent vitamin K is involved in carboxylation of glutamic acid of blood regulatory proteins C, S and Z. These proteins are systemic anticoagulants. Protein S is a cofactor of protein C, and protein Z is a cofactor of protease inhibitor serpin. Recent scientific evidence provides the more and more information that vitamin K can modify many other y-carboxyglutamic proteins (Gla proteins). Such proteins include the noncollagenous protein osteocalcin, which is important for bone physiology; the matrix Gla protein, lowering vascular calcification and is important for the prevention of atherosclerosis; Gas-6 protein, which reduces vascular smooth muscle apoptosis and inhibits formation of atherosclerotic plaques. Vitamin K acts as an electron carrier in a process called the tissue respiration of bacteria. Vitamin K is important for nervous system because it is involved in the synthesis of sphingolipids in the brain cell membrane. Vitamin K is essential for nerve impulse transmission due osteocalcin interaction with Ca2+ ions. In addition it inhibits the activity of inflammation. When treating the cancer by chemotherapy some menaquinones are useful because they inhibit proteinkinase M2 isoenzyme. The vitamin K deficiency problem is briefly described in the present article as well.
Keywords: phylloquinone, mena- quinones, y-glutamyl-carboxylase, y-carboxyglutamic acid containing proteins, blood coagulation, vascular calcification, osteocalcin, hemorrage.
