Demethylphylloquinone (BioDeep_00000009440)

描述信息

Demethylphylloquinone is a form of vitamin K that occurs in nature as part of a series of compounds with a common 2-methyl-1,4 naphthoquinone nucleus and differing isoprenoid side chains at the 3 position. Vitamin K forms comprise a single major plant form, phylloquinone with a phytyl side chain and a family of bacterially synthesized menaquinones (MKs) with multiprenyl side chains. Bacterially produced menaquinones are biologically active forms of vitamin K that are present in high concentrations in the human lower bowel. Both phylloquinone and menaquinones are bioactive in hepatic gamma-carboxylation but long-chain MKs are less well absorbed. Liver stores of vitamin K are relatively small. The hepatic reserves of phylloquinone (approximately 10\\% of the total) are labile and turn over at a faster rate than menaquinones. Vitamin K is recognised as a factor required for normal blood coagulation, and in relation to its role in bone metabolism. Vitamin K is a substrate for a liver microsomal enzyme that catalyzes the conversion of specific glutamyl residues to gamma-carboxyglutamyl residues in a limited number of proteins. These include the vitamin K-dependent clotting factors: prothrombin (factor II), factor VII, factor IX, and factor X. In the absence of vitamin K, nonfunctional clotting factors are synthesized and hemorrhage can result. Vitamin K is a coenzyme for glutamate carboxylase, which mediates the conversion of glutamate to gamma-carboxyglutamate (Gla). There are at least three Gla proteins associated with bone tissue, of which osteocalcin is the most abundant and best known. Trabecular and cortical bone appear to contain substantial concentrations of both phylloquinone and menaquinones. (PMID: 8642453, 8527227, 15018483, 1573141) [HMDB]
Demethylphylloquinone is a form of vitamin K that occurs in nature as part of a series of compounds with a common 2-methyl-1,4 naphthoquinone nucleus and differing isoprenoid side chains at the 3 position. Vitamin K forms comprise a single major plant form, phylloquinone with a phytyl side chain and a family of bacterially synthesized menaquinones (MKs) with multiprenyl side chains. Bacterially produced menaquinones are biologically active forms of vitamin K that are present in high concentrations in the human lower bowel. Both phylloquinone and menaquinones are bioactive in hepatic gamma-carboxylation but long-chain MKs are less well absorbed. Liver stores of vitamin K are relatively small. The hepatic reserves of phylloquinone (approximately 10\\% of the total) are labile and turn over at a faster rate than menaquinones. Vitamin K is recognised as a factor required for normal blood coagulation, and in relation to its role in bone metabolism. Vitamin K is a substrate for a liver microsomal enzyme that catalyzes the conversion of specific glutamyl residues to gamma-carboxyglutamyl residues in a limited number of proteins. These include the vitamin K-dependent clotting factors: prothrombin (factor II), factor VII, factor IX, and factor X. In the absence of vitamin K, nonfunctional clotting factors are synthesized and hemorrhage can result. Vitamin K is a coenzyme for glutamate carboxylase, which mediates the conversion of glutamate to gamma-carboxyglutamate (Gla). There are at least three Gla proteins associated with bone tissue, of which osteocalcin is the most abundant and best known. Trabecular and cortical bone appear to contain substantial concentrations of both phylloquinone and menaquinones. (PMID: 8642453, 8527227, 15018483, 1573141).

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