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Encyclopedia > Vitamin K
Vitamin K1 (phylloquinone). Both contain a functional naphthoquinone ring and an aliphatic side chain. Phylloquinone has a phytyl side chain.
Vitamin K1 (phylloquinone). Both contain a functional naphthoquinone ring and an aliphatic side chain. Phylloquinone has a phytyl side chain.
Vitamin K2 (menaquinone). In menaquinone the side chain is composed of a varying number of isoprenoid residues.
Vitamin K2 (menaquinone). In menaquinone the side chain is composed of a varying number of isoprenoid residues.

Vitamin K denotes a group of lipophilic, and hydrophobic, vitamins that are needed for the posttranslational modification of certain proteins, mostly required for blood coagulation. Chemically they are 2-methyl-1,4-naphthoquinone derivatives. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Naphthoquinone, or more precisely 1,4-naphthoquinone, is an organic compound. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Ketamine is a dissociative anesthetic for use in human and veterinary medicine developed by Parke-Davis (1962). ... This article or section does not cite its references or sources. ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... Retinol (Vitamin A) Vitamins are nutrients required in very small amounts for essential metabolic reactions in the body [1]. The term vitamin does not encompass other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids. ... Posttranslational modification is the chemical modification of a protein after its translation. ... Coagulation is the thickening or congealing of any liquid into solid clots. ... In chemistry a methyl-group is a hydrophobic Alkyl functional group which is derived from methane (CH4). ... 1,4-Naphthoquinone is an polycyclic aromatic ketone. ...


Vitamin K2 (menaquinone, menatetrenone) is normally produced by bacteria in the intestines, and dietary deficiency is extremely rare unless the intestines are heavily damaged. Menatetrenone (INN) is a menaquinone compound used as a hemostatic agent and as adjunctive therapy for the pain of osteoporosis. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... The intestine is the portion of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ...

Contents

Chemical structure

Vitamin K ("Koagulation" in German) is a group name for a number of related compounds, which have in common a methylated naphthoquinone ring structure, and which vary in the aliphatic side chain attached at the 3-position (see figure 1). Phylloquinone (also known as vitamin K1) invariably contains in its side chain four isoprenoid residues, one of which is unsaturated. Methylation is a term used in the chemical sciences to denote the attachment or substitution of a methyl group on various substrates. ... Naphthoquinone, or more precisely 1,4-naphthoquinone, is an organic compound. ... In chemistry, non-aromatic and non-cyclic (acyclic) organic compounds are called aliphatic. ... The term Side chain can have different meanings depending on the context: In chemistry and biochemistry a side chain is a part of a molecule attached to a core structure. ... Phylloquinone is a polycyclic aromatic ketone, based on 1,4-naphthoquinone, with 2-methyl and 3-phytyl functional groups. ... Isoprene is a common synonym for the chemical compound 2-methyl-1,3-butadiene. ...


Menaquinones have side chains composed of a variable number of unsaturated isoprenoid residues; generally they are designated as MK-n, where n specifies the number of isoprenoids.


It is generally accepted that the naphthoquinone is the functional group, so that the mechanism of action is similar for all K-vitamins. Substantial differences may be expected, however, with respect to intestinal absorption, transport, tissue distribution, and bio-availability. These differences are caused by the different lipophilicity of the various side chains, and by the different food matrices in which they occur.


Physiology

Vitamin K is involved in the carboxylation of certain glutamate residues in proteins to form gamma-carboxyglutamate residues (abbreviated Gla-residues). Gla-residues are usually involved in binding calcium. The Gla-residues are essential for the biological activity of all known Gla-proteins.[1] A carboxyl or carboxylic group is a functional group consisting of a carbon atom doubly bonded to an oxygen atom and single-bonded to a hydroxyl (-OH) group. ... Glutamate is the anion of glutamic acid. ... γ-carboxyglutamate is an uncommon amino acid found in clotting factors. ... Calcium plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. ...


At this time 14 human Gla-proteins have been discovered, and they play key roles in the regulation of three physiological processes:

  • bone metabolism (osteocalcin, also called bone Gla-protein , and matrix gla protein (MGP)).[3]
  • vascular biology.[4]

This article is about the clotting of blood. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Factor VII (formerly known as proconvertin) is one of the central proteins in the coagulation cascade. ... Factor IX (or Christmas factor or Christmas-Eve factor) is one of the serine proteases (EC 3. ... Factor X, also known by the eponym Stuart-Prower factor or as thrombokinase, is an enzyme ( EC 3. ... Protein C is a major physiological anticoagulant. ... Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the liver and it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. ... Protein Z is a member of the coagulation cascade, the group of blood proteins that leads to the formation of blood clots. ... This article is about the skeletal organs. ... Osteocalcin is a protein found in bone and dentin; that plays a role in mineralization and calcium ion homeostasis ...

Recommended amounts

The U.S. Dietary Reference Intake (DRI) for an Adequate Intake (AI) for a 25-year old male for Vitamin K is 120 micrograms/day. No Tolerable Upper Intake Level (UL) has been set. The human body stores Vitamin K, so it is not necessary to take Vitamin K daily. The Dietary Reference Intake is a system of nutrition recommendations from the Institute of Medicine of the USA National Academy (IOM). ... This article is about the Male sex. ... The U.S. National Prototype Kilogram, which currently serves as the primary standard for measuring mass in the U.S. It was assigned to the United States in 1889 and is periodically recertified and traceable to the primary international standard, The Kilogram, held at the Bureau International des Poids et...


Sources of Vitamin K

Vitamin K is found in leafy green vegetables such as spinach and lettuce; Brassica vegetables such as kale, cabbage, cauliflower, broccoli, and Brussels sprouts; wheat bran; organ meats; cereals; some fruits, such as avocado, kiwifruit and bananas; meats; cow milk and other dairy products; eggs; and soy products. Two tablespoons of parsley contains 153% of the recommended daily amount of vitamin K.[5] Binomial name Spinacia oleracea L. Percentages are relative to US recommendations for adults. ... Binomial name L. Percentages are relative to US recommendations for adults. ... Species See text. ... Kale or Borecole is a form of cabbage (Brassica oleracea Acephala Group), green in color, in which the central leaves do not form a head. ... Percentages are relative to US recommendations for adults. ... Cauliflower within Brassica oleracea, in the family Brassicaceae. ... Broccoli is a plant of the Cabbage family, Brassicaceae (formerly Cruciferae). ... The Brussels sprout (Brassica oleracea Gemmifera Group) is a cultivar group of Wild Cabbage cultivated for its small (typically 2. ... Species T. aestivum T. boeoticum T. dicoccoides T. dicoccon T. durum T. monococcum T. spelta T. sphaerococcum T. timopheevii References:   ITIS 42236 2002-09-22 Wheat Wheat For the indie rock group, see Wheat (band). ... // wheat bran Bran is the hard outer layer of and consists of combined aleurone and pericarp. ... Scrapple sandwich at the Delaware state fair Offal is the entrails and internal organs of a butchered animal. ... Grain redirects here. ... For other uses, see Fruit (disambiguation). ... Binomial name Mill. ... Binomial name C.F.Liang. ... This article is about the food. ... A glass of cows milk Milk is the nutrient fluid produced by the mammary glands of female mammals (including monotremes). ... This article is about the herb. ...


Phylloquinone (vitamin K1) is the major dietary form of vitamin K. Vitamin K1 is found in chicken egg yolk, butter, cow liver, and most cheeses. It is also found in most types of mayonnaise. Phylloquinone is a polycyclic aromatic ketone, based on 1,4-naphthoquinone, with 2-methyl and 3-phytyl functional groups. ... This article or section does not adequately cite its references or sources. ... An egg yolk surrounded by the egg white An egg yolk is the part of an egg which serves as the food source for the developing embryo inside. ... For other uses, see Butter (disambiguation). ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... For the bird, see Liver bird. ... Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ... For the song by The Smashing Pumpkins, see Mayonaise (song). ...


Role in disease

Vitamin K-deficiency may occur by disturbed intestinal uptake (such as would occur in a bile duct obstruction), by therapeutic or accidental intake of vitamin K-antagonists or, very rarely, by nutritional vitamin K-deficiency. 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 the following: risk of massive, uncontrolled internal bleeding, cartilage calcification and severe malformation of developing bone, or deposition of insoluble calcium salts in the arterial vessel walls. A bile duct is any of a number of long tube-like structures that carry bile. ...


Use on newborn babies

In some countries, injections of Vitamin K are routinely given to newborn babies. Vitamin K is used as prophylactic measure to prevent late-onset haemorrhagic disease (HDN). However, HDN is a relatively rare problem, and many parents now choose for their babies not to have such an injection. Prophylaxis refers to any medical or public health procedure whose purpose is to prevent, rather than treat or cure, disease. ... Haemorrhagic disease of the newborn is a coagulation disturbance in newborns due to vitamin K deficiency. ...


Biochemistry

Discovery

In the late 1920s, Danish scientist Henrik Dam investigated the role of cholesterol by feeding chickens a cholesterol-depleted diet.[6] After several weeks, the animals developed hemorrhages and started bleeding. These defects could not be restored by adding purified cholesterol to the diet. It appeared that - together with the cholesterol - a second compound had been extracted from the food, and this compound was called the coagulation vitamin. The new vitamin received the letter K because the initial discoveries were reported in a German journal, in which it was designated as Koagulationsvitamin. Edward Adelbert Doisy (of Saint Louis University) did much of the research that led to the discovery of the structure and chemical nature of Vitamin K.[7] Dam and Doisy shared the 1943 Nobel Prize for medicine for their work on Vitamin K. Several laboratories synthesized the compound in 1939.[8] The 1920s is sometimes referred to as the Jazz Age or the Roaring Twenties, usually applied to America. ... Henrik Dam (Full name Carl Peter Henrik Dam) (February 21, 1895 - April 18, 1976) was a Danish biochemist and physiologist. ... Cholesterol is a sterol (a combination steroid and alcohol). ... Dr. Edward Adelbert Doisy (November 3, 1893 - October 23, 1986) was an American biochemist, he was awarded the Nobel Prize in Physiology or Medicine in 1943 with Henrik Dam for their discovery of vitamin K and its chemical structure. ... Saint Louis University is a private, co-educational Catholic Jesuit university in the United States of America located in St. ... Year 1943 (MCMXLIII) was a common year starting on Friday (the link will display full 1943 calendar) of the Gregorian calendar. ... The Nobel Prize (Swedish: ), as designated in Alfred Nobels will in 1895, is awarded in Physics, Chemistry, Physiology or Medicine, Literature, and Peace. ...


For several decades the vitamin K-deficient chick model was the only method of quantitating of vitamin K in various foods: the chicks were made vitamin K-deficient and subsequently fed with known amounts of vitamin K-containing food. The extent to which blood coagulation was restored by the diet was taken as a measure for its vitamin K content.


The first published report of successful treatment with vitamin K of life-threatening hemorrhage in a jaundiced patient with prothrombin deficiency was made in 1938 at the University of Iowa Department of Pathology by Drs. Harry Pratt Smith, Emory Warner, Kenneth Brinkhous, and Walter Seegers.[9] The University of Iowa, also commonly called Iowa or locally UI, is a major coeducational research university located on a 1,900 acre (8 km²) campus in Iowa City, Iowa, US, on the banks of the Iowa River in East Central Iowa. ...


Function in the cell

The precise function of vitamin K was not discovered until 1974, when three laboratories (Stenflo et al.[10], Nelsestuen et al.[11], and Magnusson et al.[12]) isolated the vitamin K-dependent coagulation factor prothrombin (Factor II) from cows that received a high dose of a vitamin K antagonist, warfarin. It was shown that while warfarin-treated cows had a form of prothrombin that contained 10 glutamate amino acid residues near the amino terminus of this protein, the normal (untreated) cows contained 10 unusual residues which were chemically identified as gamma-carboxyglutamate, or Gla. The extra carboxyl group in Gla made clear that vitamin K plays a role in a carboxylation reaction during which Glu is converted into Gla. Year 1974 (MCMLXXIV) was a common year starting on Tuesday (link will display full calendar) of the 1974 Gregorian calendar. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Warfarin (also known under the brand names of Coumadin, Jantoven, Marevan, and Waran) is an anticoagulant medication that is administered orally or, very rarely, by injection. ... Warfarin (also known under the brand names of Coumadin, Jantoven, Marevan, and Waran) is an anticoagulant medication that is administered orally or, very rarely, by injection. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Glutamate is the anion of glutamic acid. ... This article is about the class of chemicals. ...


The biochemistry of how Vitamin K is used to convert Glu to Gla has been elucidated over the past thirty years in academic laboratories throughout the world. Within the cell, Vitamin K undergoes electron reduction to a reduced form of Vitamin K (called Vitamin K hydroquinone) by the enzyme Vitamin K epoxide reductase (or VKOR).[13] Another enzyme then oxidizes Vitamin K hydroquinone to allow carboxylation of Glu to Gla; this enzyme is called the gamma-glutamyl carboxylase[14][15] or the Vitamin K-dependent carboxylase. The carboxylation reaction will only proceed if the carboxylase enzyme is able to oxidize Vitamin K hydroquinone to vitamin K epoxide at the same time; the carboxylation and epoxidation reactions are said to be coupled reactions. Vitamin K epoxide is then re-converted to Vitamin K by the Vitamin K epoxide reductase. These two enzymes comprise the so-called Vitamin K cycle.[16] One of the reasons why Vitamin K is rarely deficient in a human diet is because Vitamin K is continually recycled in our cells. Illustration of a redox reaction Redox (shorthand for oxidation/reduction reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... Vitamin K epoxide reductase (VKOR) is an enzyme (EC 1. ... Gamma-glutamyl carboxylase is an enzyme which oxidizes Vitamin K hydroquinone. ... Vitamin K epoxide reductase (VKOR) is an enzyme (EC 1. ...


Warfarin and other coumadin drugs block the action of the Vitamin K epoxide reductase.[17] This results in decreased concentrations of Vitamin K and Vitamin K hydroquinone in the tissues, such that the carboxylation reaction catalyzed by the glutamyl carboxylase is inefficient. This results in the production of clotting factors with a greatly diminished or a complete absence of Gla. Without Gla on the amino termini of these factors, they no longer stablely bind to the blood vessel endothelium and cannot activate clotting to allow formation of a clot during tissue injury. As administration of Warfarin to a patient suppresses the clotting response, it must be carefully monitored to avoid over-dosing. See Warfarin. Warfarin (also known under the brand names of Coumadin, Jantoven, Marevan, and Waran) is an anticoagulant medication that is administered orally or, very rarely, by injection. ... Warfarin (also known under the brand name Coumadin®) is an anticoagulant medication that can be administered orally. ... Vitamin K epoxide reductase (VKOR) is an enzyme (EC 1. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... Warfarin (also known under the brand names of Coumadin, Jantoven, Marevan, and Waran) is an anticoagulant medication that is administered orally or, very rarely, by injection. ...


Gla-proteins

At present, the following human Gla-containing proteins have been characterized to the level of primary structure: the blood coagulation factors II (prothrombin), VII, IX, and X, the anticoagulant proteins C and S, and the Factor X-targeting protein Z. The bone Gla-protein osteocalcin, the calcification inhibiting matrix gla protein (MGP), the cell growth regulating growth arrest specific gene 6 protein (Gas6), and the four transmembrane Gla proteins (TMGPs) the function of which is at present unknown. Gas6 can function as a growth factor that activates the Axl receptor tyrosine kinase and stimulates cell proliferation or prevents apoptosis in some cells. In all cases in which their function was known, the presence of the Gla-residues in these proteins turned out to be essential for functional activity. Protein Z is a member of the coagulation cascade, the group of blood proteins that leads to the formation of blood clots. ... Osteocalcin is a protein found in bone and dentin; that plays a role in mineralization and calcium ion homeostasis ... The term cell growth is used in two different ways in biology. ... Growth factor is a protein that acts as a signaling molecule between cells (like cytokines and hormones) that attaches to specific receptors on the surface of a target cell and promotes differentiation and maturation of these cells. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... Tyrosine kinases are a subclass of protein kinase, see there for the principles of protein phosphorylation A tyrosine kinase (EC 2. ... A section of mouse liver showing an apoptotic cell indicated by an arrow Apoptosis (pronounced apo tō sis) is a process of suicide by a cell in a multicellular organism. ...


Gla-proteins are known to occur in a wide variety of vertebrates: mammals, birds, reptiles, and fish. The venom of a number of Australian snakes acts by activating the human blood clotting system. Remarkably, in some cases activation is accomplished by snake Gla-containing enzymes that bind to the endothelium of human blood vessels and catalyze the conversion of procoagulant clotting factors into activated ones, leading to unwanted and potentially deadly clotting. Wasp sting, with droplet of venom Venom (literally, poison of animal origin) is any of a variety of toxins used by animals, for the purpose of defense and hunting. ...


Another interesting class of invertebrate Gla-containing proteins is synthesized by the fish-hunting snail Conus geographus.[18] These snails produce a venom containing hundreds of neuro-active peptides, or conotoxins, which is sufficiently toxic to kill an adult human. Several of the conotoxins contain 2-5 Gla residues.[19]


Function in Bacteria

Many bacteria, such as Escherichia coli found in the large intestine, can synthesize Vitamin K2 (menaquinone),[20] but not Vitamin K1 (phylloquinone). In these bacteria, menaquinone will transfer two electrons between two different small molecules, in a process called anaerobic respiration.[21] For example, a small molecule with an excess of electrons (also called an electron donor) such as lactate, formate, or NADH, with the help of an enzyme, will pass two electrons to a menaquinone. The menaquinone, with the help of another enzyme, will in turn transfer these 2 electrons to a suitable oxidant, such fumarate or nitrate (also called an electron acceptor). Adding two electrons to fumarate or nitrate will convert the molecule to succinate or nitrite + water, repectively. Some of these reactions generate a cellular energy source, ATP, in a manner similar to eukaryotic cell aerobic respiration, except that the final electron acceptor is not molecular oxygen, but say fumarate or nitrate (In aerobic respiration, the final oxidant is molecular oxygen (O2) , which accepts four electrons from an electron donor such as NADH to be converted to water.) Escherichia coli can carry out aerobic respiration and menaquninone-mediated anaerobic respiration. E. coli redirects here. ... The large intestine, an organ which is now more commonly referred to by its Greek name, the colon, is the last part of the digestive system: the final stage of the alimentary canal in vertebrate animals. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... Anaerobic respiration refers to the oxidation of molecules in the absence of oxygen to produce energy, in opposition to Aerobic respiration which does use oxygen. ... Lactic acid is a chemical compound that plays a role in several biochemical processes. ... Formate or methanoate is the ion is HCOO- (formic acid minus one hydrogen ion). ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... A fumarate is a salt or ester of fumaric acid. ... Trinitrate redirects here. ... A fumarate is a salt or ester of fumaric acid. ... Trinitrate redirects here. ... Succinate is the anion of succinic acid. ... // Definition The nitrite ion is NO2−. A nitrite compound is one that contains this group, either an ionic compound, or an analogous covalent one. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... This article or section should be merged with aerobic metabolism. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance transparent (gas) very pale blue (liquid) Atomic mass 15. ... A fumarate is a salt or ester of fumaric acid. ... Trinitrate redirects here. ... This article or section should be merged with aerobic metabolism. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance transparent (gas) very pale blue (liquid) Atomic mass 15. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... E. coli redirects here. ... This article or section should be merged with aerobic metabolism. ... Anaerobic respiration refers to the oxidation of molecules in the absence of oxygen to produce energy, in opposition to Aerobic respiration which does use oxygen. ...


Carcinogenicity

Vitamin K substances are IARC Group 3 carcinogens. One study conducted in the United Kingdom found a nearly two-fold increase of leukaemia in children administered Vitamin K intramuscularly. [22] Substances, mixtures and exposure circumstances in this list have been classified by the IARC as Group 3: The agent (mixture or exposure circumstance) is not classifiable as to its carcinogenicity to humans. ... Leukemia (leukaemia in Commonwealth English) is a group of blood diseases characterized by malignancies (cancer) of the blood-forming tissues. ...


References

  1. ^ Furie B, Bouchard BA, Furie BC. Vitamin K-dependent biosynthesis of gamma-carboxyglutamic acid. Blood, 1999, 93(6):1798-808. Review
  2. ^ Mann KG. Biochemistry and physiology of blood coagulation. Thrombosis and Haemostasis, 1999, 82(2):165-74. Review. PMID: 10605701
  3. ^ Price PA. Role of vitamin-K-dependent proteins in bone metabolism, Annual Review of Nutrition, 1988, 8:565-83. Review. PMID: 3060178
  4. ^ Berkner KL, Runge KW. The physiology of vitamin K nutriture and vitamin K-dependent protein function in atherosclerosis, Journal of Thrombosis and Haemostasis, 2004, 2(12):2118-32. Review
  5. ^ http://www.nutritiondata.com/facts-C00001-01c20eX.html
  6. ^ Dam H. The antihemorrhagic vitamin of the chick. Occurrence and chemical nature, Nature, 1935;135:652
  7. ^ MacCorquodale, DW, Binkley, SB, Thayer, SA, Doisy, EA, On the constitution of Vitamin K1, Journal of the American Chemical Society, 1939, 61:1928-1929
  8. ^ Fieser, LF, Synthesis of Vitamin K1, Journal of the American Chemical Society,1939, 61:3467-3475
  9. ^ Warner, ED, Brinkhous, KM, Smith, HP, Proceedings of the Society of Experimental Biology and Medicine, 1938, 37:628
  10. ^ Stenflo J, Fernlund P, Egan W, Roepstorff P., Vitamin K-dependent modifications of glutamic acid residues in prothrombin, Proceedings of the National Academy of Sciences, USA, 1974, 71:2730–3. PMID 4528109
  11. ^ Nelsestuen GL, Zytkovicz TH, Howard JB., The mode of action of vitamin K. Identification of gamma-carboxyglutamic acid as a component of prothrombin, Journal of Biological Chemistry, 1974, 249(19):6347-50. PMID: 4214105
  12. ^ Magnusson S, Sottrup-Jensen L, Petersen TE, Morris HR, Dell A, Primary structure of the vitamin K-dependent part of prothrombin. FEBS Letters, 1974, 44(2):189-93. PMID: 4472513
  13. ^ Oldenburg J, Bevans CG, Muller CR, Watzka M, Vitamin K epoxide reductase complex subunit 1 (VKORC1): the key protein of the vitamin K cycle, Antioxidants and Redox Signaling, 2006, 8(3-4):347-53. Review. PMID: 16677080
  14. ^ Suttie JW, Vitamin K-dependent carboxylase, Annual Review of Biochemistry,1985, 54:459-77. Review. PMID: 3896125
  15. ^ Presnell SR, Stafford DW, The vitamin K-dependent carboxylase, Thrombosis and Haemostasis, 2002, 87(6):937-46. Review. PMID: 12083499
  16. ^ Stafford DW, The vitamin K cycle, Journal of Thrombosis Haemostais, 2005, (8):1873-8. Review. PMID: 16102054
  17. ^ Whitlon DS, Sadowski JA, Suttie JW, Mechanisms of coumarin action: significance of vitamin K epoxide reductase inhibition, Biochemistry, 1978, 17:1371–7. PMID 646989
  18. ^ Terlau H, Olivera BM. Conus venoms: a rich source of novel ion channel-targeted peptides, Physiological Reviews, 2004, 84(1):41-68. Review. PMID: 14715910
  19. ^ Buczek O, Bulaj G, Olivera BM, Conotoxins and the posttranslational modification of secreted gene products, Cell and Molecular Life Sciences, 2005, 62(24):3067-79. Review. PMID:16314929
  20. ^ Bentley, R, Meganathan, R., Biosynthesis of Vitamin K (menaquinone) in Bacteria, Bacteriological Reviews, 1982, 46(3):241-280. Review.
  21. ^ Haddock, BA, Jones, CW, Bacterial Respiration, Bacteriological Reviews, 1977, 41(1):74-99. Review.
  22. ^ http://www.vaclib.org/basic/vitamin-k.htm

Further reading

  • Dam, H., Researches in Vitamin K, In: Pespectives in Biological Chemistry (RE Olson, ed.), Marcel Dekker, 1970. The Nobel Prize winner recounts the history of the discovery of Vitamin K.
  • Suttie, J.W., Vitamin K, In: Handbook of Lipid research: The fat-soluble vitamins (HF DeLuca, ed.), Plenum Press, 1978. Outstanding review of Vitamin K research from 1930-1978 by one of the leaders in the field.
  • David A. Bender, Nutritional biochemistry of the vitamins, Cambridge University Press, 2003
  • G. F. M. Ball, Vitamins: their role in the human body, Blackwell Science, 2004
  • Gerald F. Combs, The vitamins: fundamental aspects in nutrition and health, Academic Press, 1998

External links


  Results from FactBites:
 
Linus Pauling Institute at Oregon State University (3018 words)
The only known biological role of vitamin K is that of the required coenzyme for a vitamin K-dependent carboxylase that catalyzes the carboxylation of the amino acid, glutamic acid, resulting in its conversion to gamma-carboxyglutamic acid (Gla) (4).
Vitamin K and childhood leukemia: Controversy arose regarding the routine use of vitamin K injections for newborns in the early 1990s when two retrospective studies were published that suggested the possibility of an association between vitamin K injections in newborns and the development of childhood leukemia and other forms of childhood cancer.
Investigators found that women whose vitamin K intake was in the lowest quintile (1/5) had a 30% higher risk of hip fracture than women with vitamin K intakes in the highest four quintiles (21).
MedlinePlus Herbs and Supplements: Vitamin K (4060 words)
Vitamin K1 (phytonadione) is the natural form of vitamin K, which is found in plants, and provides the primary source of vitamin K to humans through dietary consumption.
Vitamin K2 compounds (menaquinones) are made by bacteria in the human gut, and provide a smaller amount of the human vitamin K requirement.
Vitamin K is occasionally used to reverse warfarin before surgical procedures, although high doses are generally avoided because of the resulting delay in re-anticoagulation after the procedure.For minor procedures such as tooth extractions, some eye operations, or biopsies, reversal may not be necessary if the INR is 2.5 or lower.
  More results at FactBites »

 
 

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