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N-Acetyltaurine
''N''-Acetyltaurine (NAcT) is an endogenous metabolite. Biochemically, ''N''-acetyltaurine is formed as a result of an acetylation of taurine. The main substrate for this reaction is acetate. An increase of endogenous ''N''-acetyltaurine concentrations was observed after the consumption of alcohol and after extended physical activity (ketoacidosis). History ''N''-Acetyltaurine was first mentioned in 1990 as a compound in the droplets of the orb spider's viscid spiral. Based on its high hygroscopicity, ''N''-acetyltaurine is an important ingredient which ensures the spider web's flexibility. As a biomarker for ethanol metabolism, ''N''-acetyltaurine was first mentioned in a mice study in 2012. Another study in 2015 focused on the effect of endurance training on an increase in ''N''-acetyltaurine concentrations. The first study focusing on the forensic context of alcohol biomarker analysis in human urine was published in 2016. One year later, in 2017 an evaluation of ''N''-acety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylation
: In organic chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed ''acetate esters'' or simply ''acetates''. Deacetylation is the opposite reaction, the removal of an acetyl group from a chemical compound. Organic synthesis Acetate esters and acetamides are generally prepared by acetylations. Acetylations are often used in making C-acetyl bonds in Friedel-Crafts reactions. Carbanions and their equivalents are susceptible to acetylations. Acetylation reagents Many acetylations are achieved using these three reagents: *Acetic anhydride. This reagent is common in the laboratory; its use cogenerates acetic acid. * Acetyl chloride. This reagent is also common in the laboratory, but its use cogenerates hydrogen chloride, which can be undesirable. * Ketene. At one time acetic anhydride was prepared by the reaction of ketene with acetic acid: :H2C=C=O + CH3COOH -> (CH3C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Sulfate
Ethyl sulfate (IUPAC name: ethyl hydrogen sulfate), also known as sulfovinic acid, is an organic chemical compound used as an intermediate in the production of ethanol from ethylene. It is the ethyl ester of sulfuric acid. History This substance was studied contemporaneously with ether by German alchemist August Siegmund Frobenius in 1730, subsequently by French chemists Fourcroy in 1797 and Gay-Lussac in 1815. Swiss scientist Nicolas-Théodore de Saussure also studied it in 1807. In 1827, French chemist and pharmacist Félix-Polydore Boullay (1806-1835) along with Jean-Baptiste André Dumas noted the role of ethyl sulfate in the preparation of diethyl ether from sulfuric acid and ethanol. Further studies by the German chemist Eilhard Mitscherlich and the Swedish chemist Jöns Berzelius suggested sulfuric acid was acting as a catalyst, this eventually led to the discovery of sulfovinic acid as an intermediate in the process. The advent of electrochemistry by Italian physici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophilic Interaction Chromatography
Hydrophilic interaction chromatography (or hydrophilic interaction liquid chromatography, HILIC) is a variant of normal phase liquid chromatography that partly overlaps with other chromatographic applications such as ion chromatography and reversed phase liquid chromatography. HILIC uses hydrophilic stationary phases with reversed-phase type eluents. The name was suggested by Andrew Alpert in his 1990 paper on the subject. He described the chromatographic mechanism for it as liquid-liquid partition chromatography where analytes elute in order of increasing polarity, a conclusion supported by a review and re-evaluation of published data. Surface Any polar chromatographic surface can be used for HILIC separations. Even non-polar bonded silicas have been used with extremely high organic solvent composition, when the silica used for the chromatographic media was particularly polar. With that exception, HILIC phases can be grouped into five categories of neutral polar or io ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophilicity
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are not attracted to water and may seem to be repelled by it. Hygroscopics ''are'' attracted to water, but are not dissolved by water. Molecules A hydrophilic molecule or portion of a molecule is one whose interactions with water and other polar substances are more thermodynamically favorable than their interactions with oil or other hydrophobic solvents. They are typically charge-polarized and capable of hydrogen bonding. This makes these molecules soluble not only in water but also in other polar solvents. Hydrophilic molecules (and portions of molecules) can be contrasted with hydrophobic molecules (and portions of molecules). In some cases, both hydrophilic and hydrophobic properties occur in a single molecule. An example of these amphiphi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometry
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds. In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionized, for example by bombarding it with a beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragments) are then separated acco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Chromatography
In chemical analysis, chromatography is a laboratory technique for the separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it through a system (a column, a capillary tube, a plate, or a sheet) on which a material called the ''stationary phase'' is fixed. Because the different constituents of the mixture tend to have different affinities for the stationary phase and are retained for different lengths of time depending on their interactions with its surface sites, the constituents travel at different apparent velocities in the mobile fluid, causing them to separate. The separation is based on the differential partitioning between the mobile and the stationary phases. Subtle differences in a compound's partition coefficient result in differential retention on the stationary phase and thus affect the separation. Chromatography may be preparative or analytical. The purpose of preparativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biotransformation
Biotransformation is the biochemical modification of one chemical compound or a mixture of chemical compounds. Biotransformations can be conducted with whole cells, their lysates, or purified enzymes. Increasingly, biotransformations are effected with purified enzymes. Major industries and life-saving technologies depend on biotransformations. Advantages and disadvantages Compared to the conventional production of chemicals, biotransformations are often attractive because their selectivities can be high, limiting the coproduction of undesirable coproducts. Generally operating under mild temperatures and pressures in aqueous solutions, many biotransformations are "green". The catalysts, i.e. the enzymes, are amenable to improvement by genetic manipulation. Biotechnology usually is restrained by substrate scope. Petrochemicals for example are often not amenable to biotransformations, especially on the scale required for some applications, e.g. fuels. Biotransformations can be s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylethanol
Phosphatidylethanols (PEth) are a group of phospholipids formed only in the presence of ethanol via the action of phospholipase D (PLD). The lipid accumulates in the human body and competes at agonists sites of lipid-gated ion channels contributing to alcohol intoxication. The chemical similarity of PEth to phosphatidic acid (PA) and phosphatidylinositol 4,5-bisphosphate (PIP2) suggest a likely broad perturbation to lipid signaling; the exact role of PEth as a competitive lipid ligand has not been studied extensively. Biological synthesis When ethanol is present, PLD substitutes ethanol for water and covalently attaching the alcohol as the head group of the phospholipid; hence the name phosphatidylethanol. Normally PLD incorporates water to generate phosphatidic acid (PA); the process is termed transphosphatidylation. PLD continues to generate PA in the presence of ethanol and while PEth is generated and the effects of ethanol transphosphatidlyation are through the generation of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Glucuronide
Ethyl glucuronide (EtG) is a metabolite of ethanol which is formed in the body by glucuronidation following exposure to ethanol, usually from drinking alcoholic beverages. It is used as a biomarker to test for ethanol use and to monitor alcohol abstinence in situations where drinking is prohibited, such as by the military, in alcohol treatment programs, in professional monitoring programs (health professionals, attorneys, airline pilots in recovery from addictions), in schools, liver transplant clinics, or in recovering alcoholic patients. In addition to its use to monitor abstinence and detect drinking, EtG also has potential for monitoring the amount of alcohol use over time because it can be detected in hair and nails, though the effectiveness of this has not yet been proven. A disadvantage of the test is that because EtG can be detected in samples at very low levels, it can also be positive after exposure to alcohol from non-beverage sources, or incidental exposure, which can l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taurine
Taurine (), or 2-aminoethanesulfonic acid, is an organic compound that is widely distributed in animal tissues. It is a major constituent of bile and can be found in the large intestine, and accounts for up to 0.1% of total human body weight. It is named after Latin (cognate to Ancient Greek ταῦρος, ''taûros'') meaning bull or ox, as it was first isolated from ox bile in 1827 by German scientists Friedrich Tiedemann and Leopold Gmelin. It was discovered in human bile in 1846 by Edmund Ronalds. It has many biological roles, such as conjugation of bile acids, antioxidation, osmoregulation, membrane stabilization, and modulation of calcium signaling. It is essential for cardiovascular function, and development and function of skeletal muscle, the retina, and the central nervous system. It is an unusual example of a naturally occurring sulfonic acid. Chemical and biochemical features Taurine exists as a zwitterion , as verified by X-ray crystallography. The sulfon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatty Acid Ethyl Ester
Fatty acid esters (FAEs) are a type of ester that result from the combination of a fatty acid with an alcohol. When the alcohol component is glycerol, the fatty acid esters produced can be monoglycerides, diglycerides, or triglycerides. Dietary fats are chemically triglycerides. Esters of fatty acids are colorless, although degraded samples are sometime appear to be yellow or even brown. The triglycerides are powders, flakes, coarse powders, or granular or waxy lumps, oils or liquids. They are almost odorless. Biodiesels are typically fatty acid esters made by the transesterification of vegetable fats and oils. In this process the glycerol component is replaced with a different alcohol. The most commonly used alcohol is methanol, producing fatty acid methyl esters (FAME). When ethanol is used fatty acid ethyl esters (FAEE) are created. Other alcohols used for the production of biodiesel include butanol and isopropanol. Fatty acid ethyl esters are biomarkers for the consumption o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. as cited in Biomarkers are used in many scientific fields. Medicine Biomarkers used in the medical field, are a part of a relatively new clinical toolset categorized by their clinical applications. The three main classes are molecular biomarkers, cellular biomarkers or imaging biomarkers. All three types of biomarkers have a clinical role in narrowing or guiding treatment decisions and follow a sub-categorization of being either predictive, prognostic, or diagnostic. Predictive Predictive molecular, cellular, or imaging biomarkers that pass validation can serve as a method of predicting clinical outcomes. Predictive biomarkers are used to help optimize ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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