Bone Abstracts

Vitamin K is a group name for a number of closely related compounds. Relevant structures for this presentation are phylloquinone (vitamin K1), menaquinone-4 (MK-4) and MK-7. The latter two are members of the vitamin K2 family. The function of all forms of vitamin K is to catalyze the formation of Gla-residues, which are strong calcium-binding groups and essential for the activity of the proteins in which they occur. For calcium metabolism three Gla-proteins are of particular i...

Poor vitamin K intake is associated with markedly increased cardiovascular risk and mortality. The molecular mechanism underlying this association is suggested to be the vitamin K-dependent carboxylation of vascular matrix Gla-protein (MGP), a potent calcification inhibitor. The carboxylation step is essential for its activation, and uncarboxylated MGP, produced during poor vitamin K status, is inactive.The IDS-iSYS inaKtiv MGP assay is the auto...

Gla-rich protein (GRP) is a vitamin K-dependent protein, characterized by a high density of γ-carboxylated Glu residues and high calcium binding affinity. It was shown to accumulate in mouse and sturgeon cartilage and in sites of skin and vascular calcification in humans. Four alternatively spliced transcripts of the GRP gene (GRP–F1, F2, F3 and F4) were described in mouse chondrocytes and zebrafish. Osteoarthritis (OA) is a common degenerative joint disease...