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Ketoacid
In organic chemistry, keto acids or ketoacids (also called oxo acids or oxoacids) are organic compounds that contain a carboxylic acid group () and a ketone group ().Franz Dietrich Klingler, Wolfgang Ebertz "Oxocarboxylic Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. In several cases, the keto group is hydrated. The alpha-keto acids are especially important in biology as they are involved in the Krebs citric acid cycle and in glycolysis. Common types of keto acids include: *Alpha-keto acids, alpha-ketoacids, or 2-oxoacids have the keto group adjacent to the carboxylic acid. They often arise by oxidative deamination of amino acids, and reciprocally, they are precursors to the same. Alpha-keto acids possesses extensive chemistry as acylation agents. Furthermore, alpha-keto acids such as phenylpyruvic acid are endogenous sources for carbon monoxide (as a gasotransmitter) and pharmaceutical prodrug scaffold. Important representatives: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetoacetic Acid
Acetoacetic acid (also acetoacetate and diacetic acid) is the organic compound with the formula CHCOCHCOOH. It is the simplest beta- keto acid, and like other members of this class, it is unstable. The methyl and ethyl esters, which are quite stable, are produced on a large scale industrially as precursors to dyes. Acetoacetic acid is a weak acid. Biochemistry Under typical physiological conditions, acetoacetic acid exists as its conjugate base, acetoacetate. Acetoacetate is produced in the mitochondria of the liver from acetoacetyl coenzyme A (CoA). First, another acetyl group is added from acetyl CoA to form 3-hydroxy-3-methylglutaryl CoA, then an acetyl CoA is lost from this, yielding acetoacetate. The initial acetoacetate can come from the last cycle in the beta oxidation of a fatty acid, or it can be synthesized from two acetyl CoA molecules, catalyzed by thiolase. In mammals, acetoacetate produced in the liver (along with the other two "ketone bodies") is released ... [...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 sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketone
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' is methyl), with the formula . Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids (e.g., testosterone), and the solvent acetone. Nomenclature and etymology The word ''ketone'' is derived from ''Aketon'', an old German word for ''acetone''. According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix ''-ane'' of the parent alkane to ''-anone''. Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. These nonsystematic names are considered reta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transamination
Transamination is a chemical reaction that transfers an amino group to a ketoacid to form new amino acids. This pathway is responsible for the deamination of most amino acids. This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids (amino acids that can be synthesized de novo by the organism). Transamination in biochemistry is accomplished by enzymes called transaminases or aminotransferases. α-ketoglutarate acts as the predominant amino-group acceptor and produces glutamate as the new amino acid. : Aminoacid + α-ketoglutarate ↔ α-keto acid + glutamate Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate. : Glutamate + oxaloacetate ↔ α-ketoglutarate + aspartate Mechanism of action Transamination catalyzed by aminotransferase occurs in two stages. In the first step, the α amino group of an amino acid is transferred to the enzyme, prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO2 to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, the more formal term, carboxy-lyases ( EC number 4.1.1). In organic chemistry The term "decarboxylation" usually means replacement of a carboxyl group () with a hydrogen atom: :RCO2H -> RH + CO2 Decarboxylation is one of the oldest known organic reactions. It is one of the processes assumed to accompany pyrolysis and destructive distillation. Metal salts, especially copper compounds, facilitate the reaction via the intermediacy of metal carboxylate complexes. Decarboxylation of aryl carboxylates can generate the equivalent of the corresponding aryl anion, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citric Acid Cycle
The citric acid cycle (CAC)—also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. The Krebs cycle is used by organisms that respire (as opposed to organisms that ferment) to generate energy, either by anaerobic respiration or aerobic respiration. In addition, the cycle provides precursors of certain amino acids, as well as the reducing agent NADH, that are used in numerous other reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest components of metabolism and may have originated abiogenically. Even though it is branded as a 'cycle', it is not necessary for metabolites to follow only one specific route; at least three alternative segments of the citric acid cycle have been recognized. The name of this metabolic pathway is derived from the citric acid (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Compound
A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon (i.e., are carbocycles), none of the atoms are carbon (inorganic cyclic compounds), or where both carbon and non-carbon atoms are present ( heterocyclic compounds). Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size (e.g., < 17 total atoms) numbers in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fool's Parsley
''Aethusa cynapium'' (fool's parsley, fool's cicely, or poison parsley) is an annual (rarely biennial) herb in the flowering plant family Apiaceae, native to Europe, western Asia, and northwest Africa. It is the only member of the genus ''Aethusa''. It is related to hemlock and water-dropwort, and like them it is poisonous,Clapham, Tutin, & Warburg: Flora of the British Isles, 2nd edition, page 524 though less so than hemlock. It has been introduced into many other parts of the world and is a common weed in cultivated ground. Description It has a fusiform root and a smooth hollow branched stem growing to about high, with much divided (ternately pinnate) smooth leaves with an unpleasant smell, and small compound umbels of small irregular white flowers. Toxicity Poisoning from fool's parsley results in symptoms of heat in the mouth and throat and a post-mortem examination has shown redness of the lining membrane of the gullet and windpipe and slight congestion of the duoden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitcher Plant
Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher plants are formed by specialized leaves. The plants attract and drown their prey with nectar. Types The term "pitcher plant" generally refers to members of the Nepenthaceae and Sarraceniaceae families, but similar pitfall traps are employed by the monotypic Cephalotaceae and some members of the Bromeliaceae. The families Nepenthaceae and Sarraceniaceae are the most species-rich families of pitcher plants. The Nepenthaceae contains a single genus, ''Nepenthes'', containing over 100 species and numerous hybrids and cultivars. In this genus of Old World pitcher plants, the pitchers are borne at the end of tendrils that extend from the midrib of an otherwise unexceptional leaf. Old World pitcher plants are typically characterized as having r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conium Maculatum
''Conium maculatum'', colloquially known as hemlock, poison hemlock or wild hemlock, is a highly poisonous biennial herbaceous flowering plant in the carrot family Apiaceae, native to Europe and North Africa. A hardy plant capable of living in a variety of environments, hemlock is widely naturalized in locations outside its native range, such as parts of Australia, West Asia, and North and South America, to which it has been introduced. It is capable of spreading and thereby becoming an invasive weed. All parts of the plant are toxic, especially the seeds and roots, and especially when ingested. Under the right conditions the plant grows quite rapidly during the growing season and can reach heights of , with a long penetrating root. The plant has a distinctive odour usually considered unpleasant that carries with the wind. The hollow stems are usually spotted with a dark maroon colour before the plant dies and becomes dry and brown after completing its biennial lifecycle. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levulinic Acid
Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the formula CH3C(O)CH2CH2CO2H. It is classified as a keto acid. This white crystalline solid is soluble in water and polar organic solvents. It is derived from degradation of cellulose and is a potential precursor to biofuels, such as ethyl levulinate. Synthesis Levulinic acid was first prepared in 1840 by Dutch chemist Gerardus Johannes Mulder by heating fructose with hydrochloric acid. The first commercial production of levulinic acid began as a batchwise process in an autoclave by starch manufacturer A. E. Staley in the 1940s. In 1953 Quaker Oats developed a continuous process for the production of levulinic acid. In 1956 it was identified as a platform chemical with high potential. and in 2004 the US Department of Energy (U.S. DoE) identified levulinic acid as one of the 12 potential platform chemicals in the biorefinery concept. The synthesis of levulinic acid from hexoses (glucose, fructose) or starc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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