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Menatetrenone
Menatetrenone ( INN), also known as menaquinone-4 (MK-4), is one of the nine forms of vitamin K2. Biology MK-4 is the major form of Vitamin K in vertebrate animals, including humans and common forms of meat animals. It is produced via conversion of vitamin K1 in the body, specifically in the testes, pancreas and arterial walls. 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. K1 is converted to MK-4 in three steps: * Removal of the phytyl tail to form menadione (K3; unknown enzyme); * Reduction of menadione to menadiol (likely NQO1); * Attachment of GGPP tail to form menaquinol-4, the reduced form of MK-4 ( UBIAD1) The second and third steps are known to happen in target tissue. The first step is proposed to happen mainly in the intestines. As a medication Menatetrenone is approved in Ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menadiol
Menadiol is an organic compound with the formula C6H4(COH)2(CH)(CH3). It is formally a derivative of p-hydroquinone. The name vitamin K4 can refer to: * specifically this compound, * its various esters, e.g. ** menadiol diacetate (acetomenaphthone), ** menadiol dibutyrate, ** menadiol dimalonate, or * its various salts, like ** menadiol sodium diphosphate (Kappadione) ** menadiol sodium disulfate. Menadiol sodium diphosphate is approved in the UK for treatment and prevention of haemorrhage, mainly in obstructive jaundice (before and after surgery). Menadiol is probably naturally produced by reduction of menadione ("vitamin K3"; see ) as an intermediate in the conversion from K3 to MK-4. It can be oxidized in experimental conditions back to menadione. Phylloquinone structure.svg, The menadiol core is apparent in the structure of vitamin K Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
By Mouth
Oral administration is a route of administration whereby a substance is taken through the Human mouth, mouth, swallowed, and then processed via the digestive system. This is a common route of administration for many medications. Oral administration can be easier and less painful than other routes of administration, such as Injection (medicine), injection. However, the onset of action is relatively low, and the effectiveness is reduced if it is not absorbed properly in the digestive system, or if it is broken down by digestive enzymes before it can reach the bloodstream. Some medications may cause gastrointestinal side effects, such as nausea or vomiting, when taken orally. Oral administration can also only be applied to conscious patients, and patients able to swallow. Terminology ''Per os'' (; ''P.O.'') is an adverbial phrase meaning literally from Latin "through the mouth" or "by mouth". The expression is used in medicine to describe a treatment that is taken orally (but not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K2
Vitamin K2 or menaquinone (MK) () is one of three types of vitamin K, 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 commonly found in animal products. However, at least one published study concluded that "MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels." The MK-4 in animal (including human) tissue is made from dietary plant vitamin K1. This process can be accomplished by animal tissues alone, as it proceeds in germ-free rodents. * Long-chain menaquinones (longer than MK-4) include ... [...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 NQO1. 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. As K3 is known to be toxic in large amounts, researchers speculate that the cleavage process is closely regulated. Terminology The compound is variously known as vitamin K3 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NQO1
NAD(P)H dehydrogenase uinone1 is an enzyme that in humans is encoded by the ''NQO1'' gene. This protein-coding gene is a member of the NAD(P)H dehydrogenase (quinone) family and encodes a 2-electron reductase (enzyme). This FAD-binding protein forms homodimers and performs two-electron reduction of quinones to hydroquinones and of other redox dyes. It has a preference for short-chain acceptor quinones, such as ubiquinone, benzoquinone, juglone and duroquinone. This gene has an important paralog NQO2. This protein is located in the cytosol. NQO1 enzyme expression can be induced by dioxin and inhibited by dicoumarol. Function This gene is a member of the NAD(P)H dehydrogenase (quinone) family and encodes a cytoplasmic 2-electron reductase. This FAD-binding protein forms homodimers and reduces quinones to hydroquinones. This enzyme facilitates the two electron reduction of quinone to hydroquinone. NQO1-mediated two electron reduction of quinone to hydroquinone thereby indirectl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UBIAD1
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) also known as transitional epithelial response protein 1 (TERE1) is a protein that in humans is encoded by the ''UBIAD1'' gene. The enzyme is named for its canonical role in ubiquinone production, catalyzing reaction EC 2.5.1.39; it thus has a role in oxidative stress pathways. Recent evidence suggests that UBIAD1 has enzymatic activity in the vitamin K pathway, converting menadione to MK-4. This translates to a role in blood vessel development in zebrafish.R Postel, Identification and Characterization of Novel Genes by Reverse and Forward Genetics in Zebrafish, igitur-archive.library.uu.nl/dissertations/2008-0522.../UUindex.html, 2008. Clinical significance Mutations of the UBIAD1 gene cause Schnyder crystalline corneal dystrophy Schnyder crystalline corneal dystrophy (SCD) is a rare form of corneal dystrophy. It is caused by heterozygous mutations in UBIAD1 gene.Weiss et al, IOVS (2007) vol 48, 5007-5012 Cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postmenopausal Osteoporosis
Menopause, also known as the climacteric, is the time when menstrual periods permanently stop, marking the end of the reproductive stage for the female human. It typically occurs between the ages of 45 and 55, although the exact timing can vary. Menopause is usually a natural change related to a decrease in circulating blood estrogen levels. It can occur earlier in those who smoke tobacco. Other causes include surgery that removes both ovaries, some types of chemotherapy, or anything that leads to a decrease in hormone levels. At the physiological level, menopause happens because of a decrease in the ovaries' production of the hormones estrogen and progesterone. While typically not needed, measuring hormone levels in the blood or urine can confirm a diagnosis. Menopause is the opposite of menarche, the time when periods start. In the years before menopause, a woman's periods typically become irregular, which means that periods may be longer or shorter in duration, or be l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daily Value
In the U.S. and Canada, the Reference Daily Intake (RDI) is used in nutrition labeling on food and dietary supplement products to indicate the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of healthy individuals in every demographic in the United States. While developed for the US population, it has been adopted by Canada. The RDI is used to determine the Daily Value (DV) of foods, which is printed on nutrition facts labels (as %DV) in the United States and Canada, and is regulated by the Food and Drug Administration (FDA) and by Health Canada, respectively. The labels "high", "rich in", or "excellent source of" may be used for a food if it contains 20% or more of the DV. The labels "good source", "contains", or "provides" may be used on a food if it contains between 10% and 20% of the DV, and "low source" applies if the %DV is 5% or lower. The Recommended Dietary Allowances (RDAs) were a set of nutrition recommenda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteocalcin
Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein (BGLAP), is a small (49-amino-acid) noncollagenous protein hormone found in bone and dentin, first identified as a calcium-binding protein. Because osteocalcin has gla domains, its synthesis is vitamin K2-dependent. In humans, osteocalcin is encoded by the ''BGLAP'' gene. Its receptors include GPRC6A, GPR158, and possibly a third, yet-to-be-identified receptor. There is evidence that GPR37 might be the third osteocalcin receptor. Function Osteocalcin is secreted solely by osteoblasts and is thought to play a role in the body's metabolic regulation. In its carboxylated form, calcium is bound directly to the bone and thus concentrates here. In its uncarboxylated form, osteocalcin acts as a hormone in the body, signalling in the pancreas, fat, muscle, testes, and brain. * In the pancreas, osteocalcin acts on beta cells, causing beta cells in the pancreas to release more insulin. * In fat cel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpenes
Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. Some diterpenes are known to be antimicrobial and anti-inflammatory. Structures As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present. Biosynthesis Diterpenes are derived from the addition of one IPP unit to FPP to form geranylgeranyl pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and cytochromes P450. Several diterpenes are produced by plants and cyanobacteria. GGPP is also the precursor for the synthesis of the phytane by the action of the enzyme geran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
