Vita Kbv

VITAMIN K

Background

Vitamin K is involved in the formation of calcium-binding groups in proteins. These calcium-binding groups are called Gla-residues, and the proteins containing these residues are designated as Gla-proteins. The Gla-residues are essential for the biological activity of all Gla-proteins. At this time not more than 12 human Gla-proteins have been discovered, and they play key roles in the regulation of three physiological processes:

* blood coagulation

* bone metabolism

* vascular biology

Vitamin K-deficiency may occur by either poor dietary vitamin K intake, disturbed intestinal uptake (e.g. caused by a bile duct obstruction), or by therapeutic or accidental intake of vitamin K-antagonists. As a result of the acquired vitamin K-deficiency, Gla-residues are not or incompletely formed and hence the Gla-proteins are inactive. Lack of control of the three processes mentioned above may lead to:

1. risk of uncontrolled and severe bleeding 2. cartilage calcification and severe malformation of developing bone

sufficient vit K	insufficient vit K
3. deposition of insoluble calcium salts in the arterial vessel wall

sufficient vit K	insufficient vit K

On the following pages we will describe in more detail our knowledge on vitamin K and vitamin K-dependent processes as well as new insights on human vitamin K requirement.