Keto Acids
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Keto Acids
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: ** ...
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Citric Acid Cycle
The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle)—is a series of chemical reaction, biochemical reactions that release the energy stored in nutrients through acetyl-CoA Redox, oxidation. The energy released is available in the form of Adenosine triphosphate, ATP. The Hans Krebs (biochemist), Krebs cycle is used by organisms that generate energy via Cellular respiration, respiration, either anaerobic respiration, anaerobically or aerobic respiration, aerobically (organisms that Fermentation, ferment use different pathways). In addition, the cycle provides precursor (chemistry), precursors of certain amino acids, as well as the reducing agent nicotinamide adenine dinucleotide, NADH, which are used in other reactions. Its central importance to many Metabolic pathway, biochemical pathways suggests that it was one of the earliest metabolism components. Even though it is branded as a "cycle", it is not necessa ...
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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 with rings containing both carbon and non-carbon). 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 ...
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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. Chemical composition, toxicity and medical uses ''A. cynapium'' is poisonous when fresh, but safe if dried. ''A. cynapiums toxic effects are caused at least in part by cynopine, which resembles coniine in its physical and ...
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Pitcher Plant
Pitcher plants are carnivorous plants known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of pitcher plant are considered to be "true" pitcher plants and are formed by specialized leaves. The plants attract and drown the 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. Nepenthaceae 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 reduced and ...
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Conium Maculatum
''Conium maculatum'', commonly known as hemlock (British English) or poison hemlock (American English), is a highly poisonous flowering plant in the carrot family Apiaceae, native to Europe and North Africa. It is Herbaceous plant, herbaceous, with no woody parts, and has a Biennial plant, biennial lifecycle. Hemlock is a hardy plant capable of living in a variety of environments and is now widely naturalised in locations outside its native range, including 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 plant, invasive weed. All parts of the hemlock plant are Toxic plant, toxic, particularly 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 Taproot, penetrating root. The plant has a distinctive odour that is usually considered unpleasant and carries with ...
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Levulinic Acid
Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the chemical formula, 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, fructo ...
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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 (Enzyme Commission number, EC number 4.1.1). In organic chemistry The term "decarboxylation" usually means replacement of a carboxyl group () with a hydrogen atom: : Decarboxylation is one of the oldest known organic reactions. It is one of the processes assumed to accompany pyrolysis and destructive distillation. Overall, decarboxylation depends upon stability of the carbanion synthon , although the anion may not be a true chemical intermediate. Typically, carboxylic acids decarboxylate slowly, but carboxylic acids with an α el ...
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Claisen Condensation
The Claisen condensation is a carbon–carbon bond forming reaction that occurs between two esters or one ester and another carbonyl compound in the presence of a strong base. The reaction produces a β-keto ester or a β- diketone. It is named after Rainer Ludwig Claisen, who first published his work on the reaction in 1887. The reaction has often been displaced by diketene-based chemistry, which affords acetoacetic esters. Requirements At least one of the reagents must be enolizable (have an α-proton and be able to undergo deprotonation to form the enolate anion). There are a number of different combinations of enolizable and nonenolizable carbonyl compounds that form a few different types of Claisen. The base used must not interfere with the reaction by undergoing nucleophilic substitution or addition with a carbonyl carbon. For this reason, the conjugate sodium alkoxide base of the alcohol formed (e.g. sodium ethoxide if ethanol is formed) is often used, since the a ...
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Acetoacetic Acid
Acetoacetic acid ( IUPAC name: 3-oxobutanoic acid, also known as acetonecarboxylic acid or 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: : Unbound acetoacetate is primarily produced by liver mitochondria from its thioester with coenzyme A (CoA): : The acetoacetyl-CoA itself is formed by three routes: *3-hydroxy-3-methylglutaryl CoA releases acetyl CoA and acetoacetate: *: *Acetoacetyl-CoA can come from beta oxidation of butyryl-CoA: *: *Condensation of pair of acetyl CoA molecules as catalyzed by thiolase. *: In mammals, acetoacetate produced in the liver (along with the other two " ketone bodies") is ...
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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. :Amino acid, Aminoacid + α-ketoglutarate ↔ α-keto acid + Glutamic acid, glutamate Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate. :Glutamic acid, 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 ...
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Coenzyme
A cofactor is a non-protein chemical compound or Metal ions in aqueous solution, metallic ion that is required for an enzyme's role as a catalysis, catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that assist in Biochemistry, biochemical transformations. The rates at which these happen are characterized in an area of study called enzyme kinetics. Cofactors typically differ from Ligand (biochemistry), ligands in that they often derive their function by remaining bound. Cofactors can be classified into two types: inorganic ions and complex organic molecules called Enzyme#Coenzymes, coenzymes. Coenzymes are mostly derived from vitamins and other organic essential nutrients in small amounts. (Some scientists limit the use of the term "cofactor" for inorganic substances; both types are included here.) Coenzymes are further divided into two types. The first is called a "prosthetic group", which consists ...
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