Recent trends in the metabolism and cell biology of vitamin K with special reference to vitamin K cycling and MK-4 biosynthesis.
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Shearer MJ, Newman P
Recent trends in the metabolism and cell biology of vitamin K with special reference to vitamin K cycling and MK-4 biosynthesis.
J Lipid Res. 2014 Mar;55(3):345-62. doi: 10.1194/jlr.R045559. Epub 2014 Jan 31.
- PubMed ID
- 24489112 [ View in PubMed]
- Abstract
In contrast to other fat-soluble vitamins, dietary vitamin K is rapidly lost to the body resulting in comparatively low tissue stores. Deficiency is kept at bay by the ubiquity of vitamin K in the diet, synthesis by gut microflora in some species, and relatively low vitamin K cofactor requirements for gamma-glutamyl carboxylation. However, as shown by fatal neonatal bleeding in mice that lack vitamin K epoxide reductase (VKOR), the low requirements are dependent on the ability of animals to regenerate vitamin K from its epoxide metabolite via the vitamin K cycle. The identification of the genes encoding VKOR and its paralog VKOR-like 1 (VKORL1) has accelerated understanding of the enzymology of this salvage pathway. In parallel, a novel human enzyme that participates in the cellular conversion of phylloquinone to menaquinone (MK)-4 was identified as UbiA prenyltransferase-containing domain 1 (UBIAD1). Recent studies suggest that side-chain cleavage of oral phylloquinone occurs in the intestine, and that menadione is a circulating precursor of tissue MK-4. The mechanisms and functions of vitamin K recycling and MK-4 synthesis have dominated advances made in vitamin K biochemistry over the last five years and, after a brief overview of general metabolism, are the main focuses of this review.
DrugBank Data that Cites this Article
- Drugs
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Phylloquinone Vitamin K-dependent gamma-carboxylase Protein Humans YesSubstrateInducerCofactorDetails - Drug Enzymes
Drug Enzyme Kind Organism Pharmacological Action Actions Phylloquinone UbiA prenyltransferase domain-containing protein 1 Protein Humans UnknownSubstrateDetails Phylloquinone Vitamin K epoxide reductase complex subunit 1 Protein Humans UnknownSubstrateProduct ofDetails - Drug Reactions
Reaction Details