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Vitamin K: an old vitamin in a new perspective.

Gröber U, Reichrath J, Holick MF, Kisters K - Dermatoendocrinol (2015)

Bottom Line: Vitamin K1 (phylloquinone) is more abundant in foods but less bioactive than the vitamin K2 menaquinones (especially MK-7, menaquinone-7).Vitamin K compounds undergo oxidation-reduction cycling within the endoplasmic reticulum membrane, donating electrons to activate specific proteins via enzymatic gamma-carboxylation of glutamate groups before being enzymatically reduced.The following review describes the history of vitamin K, the physiological significance of the K vitamers, updates skeletal and cardiovascular benefits and important interactions with drugs.

View Article: PubMed Central - PubMed

Affiliation: Academy for Micronutrient Medicine ; Essen, Germany.

ABSTRACT
The topic of "Vitamin K" is currently booming on the health products market. Vitamin K is known to be important for blood coagulation. Current research increasingly indicates that the antihaemorrhagic vitamin has a considerable benefit in the prevention and treatment of bone and vascular disease. Vitamin K1 (phylloquinone) is more abundant in foods but less bioactive than the vitamin K2 menaquinones (especially MK-7, menaquinone-7). Vitamin K compounds undergo oxidation-reduction cycling within the endoplasmic reticulum membrane, donating electrons to activate specific proteins via enzymatic gamma-carboxylation of glutamate groups before being enzymatically reduced. Along with coagulation factors (II, VII, IX, X, and prothrombin), protein C and protein S, osteocalcin (OC), matrix Gla protein (MGP), periostin, Gas6, and other vitamin K-dependent (VKD) proteins support calcium homeostasis, inhibit vessel wall calcification, support endothelial integrity, facilitate bone mineralization, are involved in tissue renewal and cell growth control, and have numerous other effects. The following review describes the history of vitamin K, the physiological significance of the K vitamers, updates skeletal and cardiovascular benefits and important interactions with drugs.

No MeSH data available.


Related in: MedlinePlus

In the vitamin K cycle, vitamin K-dependent gamma-carboxyglutamic acid (Gla) proteins are carboxylated and activated.
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f0001: In the vitamin K cycle, vitamin K-dependent gamma-carboxyglutamic acid (Gla) proteins are carboxylated and activated.

Mentions: In this context, the significance of the vitamin K cycle was also recognized: γ-carboxylation is catalyzed by a microsomal carboxylase and requires CO2 and molecular oxygen. Vitamin K hydroquinone is required as a cofactor. The oxidation of the hydroquinone to vitamin K 2,3-epoxide supplies the energy required for the abstraction of a proton of the gamma carbon of the glutamic acid (Glu) residue, resulting in a carbanion, which is then carboxylated to γ-carboxyglutamic acid (Gla) (Fig. 1). Vitamin K 2,3-epoxide is subsequently regenerated to vitamin K hydroquinone by the enzymes vitamin K epoxide and quinone reductase.10-12 The γ-carboxylation is thus characterized by a cyclical transformation, in which oxidised and reduced forms of vitamin K are involved as the driving factors. The inhibition of these 2 enzymes by vitamin K antagonists, such as phenprocoumon and warfarin, has considerable medical significance, which is utilised in anticoagulation therapy.13 Currently, approximately 14 vitamin K-dependent proteins are known, with broad spectrum efficacy on haemostasis, calcium metabolism, control of cell growth, apoptosis and signal transduction (Table 1).14-17 Following elucidation of the vitamin's haemostasiological significance and research into further vitamin K-dependent Gla proteins, such as osteocalcin (BGP = bone Gla protein) and matrix Gla protein (MGP), current research is focusing on the vitamin's effect on bone and vascular health.10,13,18Table 1.


Vitamin K: an old vitamin in a new perspective.

Gröber U, Reichrath J, Holick MF, Kisters K - Dermatoendocrinol (2015)

In the vitamin K cycle, vitamin K-dependent gamma-carboxyglutamic acid (Gla) proteins are carboxylated and activated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4580041&req=5

f0001: In the vitamin K cycle, vitamin K-dependent gamma-carboxyglutamic acid (Gla) proteins are carboxylated and activated.
Mentions: In this context, the significance of the vitamin K cycle was also recognized: γ-carboxylation is catalyzed by a microsomal carboxylase and requires CO2 and molecular oxygen. Vitamin K hydroquinone is required as a cofactor. The oxidation of the hydroquinone to vitamin K 2,3-epoxide supplies the energy required for the abstraction of a proton of the gamma carbon of the glutamic acid (Glu) residue, resulting in a carbanion, which is then carboxylated to γ-carboxyglutamic acid (Gla) (Fig. 1). Vitamin K 2,3-epoxide is subsequently regenerated to vitamin K hydroquinone by the enzymes vitamin K epoxide and quinone reductase.10-12 The γ-carboxylation is thus characterized by a cyclical transformation, in which oxidised and reduced forms of vitamin K are involved as the driving factors. The inhibition of these 2 enzymes by vitamin K antagonists, such as phenprocoumon and warfarin, has considerable medical significance, which is utilised in anticoagulation therapy.13 Currently, approximately 14 vitamin K-dependent proteins are known, with broad spectrum efficacy on haemostasis, calcium metabolism, control of cell growth, apoptosis and signal transduction (Table 1).14-17 Following elucidation of the vitamin's haemostasiological significance and research into further vitamin K-dependent Gla proteins, such as osteocalcin (BGP = bone Gla protein) and matrix Gla protein (MGP), current research is focusing on the vitamin's effect on bone and vascular health.10,13,18Table 1.

Bottom Line: Vitamin K1 (phylloquinone) is more abundant in foods but less bioactive than the vitamin K2 menaquinones (especially MK-7, menaquinone-7).Vitamin K compounds undergo oxidation-reduction cycling within the endoplasmic reticulum membrane, donating electrons to activate specific proteins via enzymatic gamma-carboxylation of glutamate groups before being enzymatically reduced.The following review describes the history of vitamin K, the physiological significance of the K vitamers, updates skeletal and cardiovascular benefits and important interactions with drugs.

View Article: PubMed Central - PubMed

Affiliation: Academy for Micronutrient Medicine ; Essen, Germany.

ABSTRACT
The topic of "Vitamin K" is currently booming on the health products market. Vitamin K is known to be important for blood coagulation. Current research increasingly indicates that the antihaemorrhagic vitamin has a considerable benefit in the prevention and treatment of bone and vascular disease. Vitamin K1 (phylloquinone) is more abundant in foods but less bioactive than the vitamin K2 menaquinones (especially MK-7, menaquinone-7). Vitamin K compounds undergo oxidation-reduction cycling within the endoplasmic reticulum membrane, donating electrons to activate specific proteins via enzymatic gamma-carboxylation of glutamate groups before being enzymatically reduced. Along with coagulation factors (II, VII, IX, X, and prothrombin), protein C and protein S, osteocalcin (OC), matrix Gla protein (MGP), periostin, Gas6, and other vitamin K-dependent (VKD) proteins support calcium homeostasis, inhibit vessel wall calcification, support endothelial integrity, facilitate bone mineralization, are involved in tissue renewal and cell growth control, and have numerous other effects. The following review describes the history of vitamin K, the physiological significance of the K vitamers, updates skeletal and cardiovascular benefits and important interactions with drugs.

No MeSH data available.


Related in: MedlinePlus