|
Menaquinone
Vitamin K2 or menaquinone (MK) () is one of three types of vitamin K Vitamin K refers to structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation ..., the other two being vitamin K1 (phylloquinone) and K3 (menadione). K2 is both a tissue and bacterial product (derived from vitamin K1 in both cases) and is usually found in animal products or fermented foods. The number ''n'' of isoprenyl units in their side chain differs and ranges from 4 to 13, hence Vitamin K2 consists of various forms. It is indicated as a suffix (-n), e. g. MK-7 or MK-9. The most common in the human diet is the short-chain, water-soluble menatetrenone (MK-4), which is usually produced by tissue and/or bacterial conversion of vitamin K1, and is commonly found in animal products. It is known that production of MK-4 from dietary plant vitamin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K
Vitamin K refers to structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation (K from ''Koagulation'', German for "coagulation") or for controlling binding of calcium in bones and other tissues. The complete synthesis involves final modification of these so-called "Gla proteins" by the enzyme gamma-glutamyl carboxylase that uses vitamin K as a cofactor. Vitamin K is used in the liver as the intermediate VKH2 to deprotonate a glutamate residue and then is reprocessed into vitamin K through a vitamin K oxide intermediate. The presence of uncarboxylated proteins indicates a vitamin K deficiency. Carboxylation allows them to bind (chelate) calcium ions, which they cannot do otherwise. Without vitamin K, blood coagulation is seriously impaired, and uncontrolled bleeding occurs. Research suggests that deficiency of v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menatetrenone
Menatetrenone (INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...), also known as MK-4, is one of the nine forms of vitamin K2. MK-4 is produced via conversion of vitamin K1 in the body, in the testes, pancreas and arterial walls. While major questions still surround the biochemical pathway for the transformation of vitamin K1 to MK-4, studies demonstrate the conversion is not dependent on gut bacteria, occurring in germ-free rats and in parenterally-administered K1 in rats. Tissues that accumulate high amounts of MK-4 have a capacity to convert up to 90% of the available K1 into MK-4. Dose Bioavailability studies have shown that small oral doses are not detected in the blood – for example 420 mcg of menatetrenone or less tested over minutes and hours are not detectable, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytomenadione
Phytomenadione, also known as vitamin K1 or phylloquinone, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines. As a supplement it is used to treat certain bleeding disorders. This includes warfarin overdose, vitamin K deficiency, and obstructive jaundice. It is also recommended to prevent and treat vitamin K deficiency bleeding in infants. Use is typically recommended by mouth, intramuscular injection or injection under the skin. When given by injection benefits are seen within two hours. Many countries in the world choose intramuscular injections in newborn to keep them safe from severe bleeding (VKDB). It is considered a safe treatment and saves many children from death and severe neurologic deficit every year. Side effects when given by injection may include pain at the site of injection. Severe allergic reactions may occur when it is injected into a vein or muscle, but this has mainly happened ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylloquinone
Phytomenadione, also known as vitamin K1 or phylloquinone, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines. As a supplement it is used to treat certain bleeding disorders. This includes warfarin overdose, vitamin K deficiency, and obstructive jaundice. It is also recommended to prevent and treat vitamin K deficiency bleeding in infants. Use is typically recommended by mouth, intramuscular injection or injection under the skin. When given by injection benefits are seen within two hours. Many countries in the world choose intramuscular injections in newborn to keep them safe from severe bleeding (VKDB). It is considered a safe treatment and saves many children from death and severe neurologic deficit every year. Side effects when given by injection may include pain at the site of injection. Severe allergic reactions may occur when it is injected into a vein or muscle, but this has mainly happened ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menadione
Menadione is a natural organic compound with the formula C6H4(CO)2C2H(CH3). It is an analog of 1,4-naphthoquinone with a methyl group in the 2-position. It is sometimes called vitamin K3. Use is allowed as a nutritional supplement in animal feed because of its vitamin K activity. Biochemistry Menadione is converted to vitamin K2 (specifically, MK-4) by the prenyltransferase action of vertebrate UBIAD1. This reaction requires the hydroquinone (reduced) form of K3, menadiol, produced by an unidentified enzyme. Menadione is also a circulating form of vitamin K, produced in small amounts (1–5%) after intestinal absorption of K1 and K2. This circulation explains the uneven tissue distribution of MK-4, especially since menadione can penetrate the blood–brain barrier. The cleavage enzyme is yet to be identified. Terminology The compound is variously known as vitamin K3 and provitamin K3. Proponents of the latter name generally argue that the compound is not a real vitamin due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K Structures
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term ''vitamin'' does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, there are eight vitamers of vitamin E: four tocopherols and four tocotrienols. Some sources list fourteen vitamins, by including choline, but major health organizations list thirteen: vitamin A (as all-''trans''-retinol, all-''trans''- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K3
Menadione is a natural organic compound with the formula C6H4(CO)2C2H(CH3). It is an analog of 1,4-naphthoquinone with a methyl group in the 2-position. It is sometimes called vitamin K3. Use is allowed as a nutritional supplement in animal feed because of its vitamin K activity. Biochemistry Menadione is converted to vitamin K2 (specifically, MK-4) by the prenyltransferase action of vertebrate UBIAD1. This reaction requires the hydroquinone (reduced) form of K3, menadiol, produced by an unidentified enzyme. Menadione is also a circulating form of vitamin K, produced in small amounts (1–5%) after intestinal absorption of K1 and K2. This circulation explains the uneven tissue distribution of MK-4, especially since menadione can penetrate the blood–brain barrier. The cleavage enzyme is yet to be identified. Terminology The compound is variously known as vitamin K3 and provitamin K3. Proponents of the latter name generally argue that the compound is not a real vitamin due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylation Reaction Vitamin K Cycle
Carboxylation is a chemical reaction in which a carboxylic acid is produced by treating a substrate with carbon dioxide. The opposite reaction is decarboxylation. In chemistry, the term carbonation is sometimes used synonymously with carboxylation, especially when applied to the reaction of carbanionic reagents with CO2. More generally, carbonation usually describes the production of carbonates. Organic chemistry Carboxylation is a standard conversion in organic chemistry. Specifically carbonation (i.e. carboxylation) of Grignard reagents and organolithium compounds is a classic way to convert organic halides into carboxylic acids. Sodium salicylate, precursor to aspirin, is commercially prepared by treating sodium phenolate (the sodium salt of phenol) with carbon dioxide at high pressure (100 atm) and high temperature (390 K) – a method known as the Kolbe-Schmitt reaction. Acidification of the resulting salicylate salt gives salicylic acid. : Many detailed procedures are desc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gla Domain
Vitamin K-dependent carboxylation/gamma-carboxyglutamic (GLA) domain is a protein domain that contains post-translational modifications of many glutamate residues by vitamin K-dependent carboxylation to form γ-carboxyglutamate (Gla). Proteins with this domain are known informally as Gla proteins. The Gla residues are responsible for the high-affinity binding of calcium ions. The GLA domain binds calcium ions by chelating them between two carboxylic acid residues. These residues are part of a region that starts at the N-terminal extremity of the mature form of Gla proteins, and that ends with a conserved aromatic residue. This results in a conserved Gla-x(3)-Gla-x-Cys motif that is found in the middle of the domain, and which seems to be important for substrate recognition by the carboxylase. The 3D structures of several Gla domains have been solved. Calcium ions induce conformational changes in the Gla domain and are necessary for the Gla domain to fold properly. A common structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamic Acid
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABA-ergic neurons. Its molecular formula is . Glutamic acid exists in three optically isomeric forms; the dextrorotatory -form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971. Its molecular structure could be idealized as HOOC−CH()−()2−COOH, with two carboxyl groups −COOH and one amino group −. However, in the solid state and mildly acidic water solutio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factor II
Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma-thrombin'') is a serine protease, an enzyme that, in humans, is encoded by the ''F2'' gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions. History After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872. Prothrombin was discovered by Pekelharing in 1894. Physiology Synthesis Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
