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3-hydroxypropionate Cycle
The 3-Hydroxypropionate bicycle, also known as the 3-Hydroxypropionate pathway, is a process that allows some bacteria to generate 3-Hydroxypropionic acid, 3-Hydroxypropionate utilizing carbon dioxide. In this pathway CO2 is fixed (i.e. incorporated) by the action of two enzymes, acetyl-CoA carboxylase and propionyl-CoA carboxylase. These enzymes generate malonyl-CoA and methylmalonyl-CoA, (''S'')-methylmalonyl-CoA, respectively. Malonyl-CoA, in a series of reactions is further split into acetyl-CoA and glyoxylate. Glyoxylate is incorporated into beta-methylmalyl-coA which is then split, again through a series of reactions to release pyruvate as well as acetate, which is used to replenish the cycle. This pathway has been demonstrated in ''Chloroflexus'', a nonsulfur photosynthetic bacterium, however other studies suggest that 3-hydroxypropionate bicycle is utilized by several chemotrophic archaea. See also * Carbon fixation References External links Pathways Metabolic pathw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-Hydroxypropionic Acid
3-Hydroxypropionic acid is a carboxylic acid, specifically a beta hydroxy acid. It is an acidic viscous liquid with a pKa of 4.5. It is very soluble in water, soluble in ethanol and diethyl ether. Upon distillation, it dehydration reaction, dehydrates to form acrylic acid, and is occasionally called hydracrylic acid 3-Hydroxypropionic acid is used in the industrial production of various chemicals such as acrylates. Synthesis 3-Hydroxypropionic acid can be obtained by base-induced hydration of acrylic acid followed by reacidification. Another synthesis involves cyanation of ethylene chlorohydrin followed by hydrolysis of the resulting nitrile. Hydrolysis of propiolactone is yet another route. Potential applications The polyester poly(3-hydroxypropionic acid) is a biodegradable polymer. The method combines the high-molecular weight and control aspects of ring-opening polymerization with the commercial availability of the beta hydroxy acid, 3-hydroxypropionic acid which is abbrevi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetyl-CoA Carboxylase
Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme () that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-CoA through its two catalytic activities, biotin carboxylase (BC) and carboxyltransferase (CT). ACC is a multi-subunit enzyme in most prokaryotes and in the chloroplasts of most plants and algae, whereas it is a large, multi-domain enzyme in the cytoplasm of most eukaryotes. The most important function of ACC is to provide the malonyl-CoA substrate for the biosynthesis of fatty acids. The activity of ACC can be controlled at the transcriptional level as well as by small molecule modulators and covalent modification. The human genome contains the genes for two different ACCs—'' ACACA'' and ''ACACB''. Structure Prokaryotes and plants have multi-subunit ACCs composed of several polypeptides. Biotin carboxylase (BC) activity, biotin carboxyl carrier protein (BCCP), and carboxyl transferase (CT) activity are each contained on a different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propionyl-CoA Carboxylase
Propionyl-CoA carboxylase (, PCC) catalyses the carboxylation reaction of propionyl-CoA in the mitochondrial matrix. PCC has been classified both as a ligase and a lyase. The enzyme is biotin-dependent. The product of the reaction is (S)-methylmalonyl CoA. : ATP + propionyl-CoA + HCO3− ADP + phosphate + (S)-methylmalonyl-CoA (S)-Methylmalonyl-CoA cannot be directly utilized by animals. It is acted upon by a racemase, yielding (R)-methylmalonyl-CoA, which is then converted into succinyl-CoA by methylmalonyl-CoA mutase (one of the few metabolic enzymes which requires vitamin B12 as a cofactor). Succinyl-CoA, a Krebs cycle intermediate, is further metabolized into fumarate, then malate, and then oxaloacetate. Oxaloacetate may be transported into the cytosol to form phosphoenol pyruvate and other gluconeogenic intermediates. Propionyl-CoA is therefore an important precursor to glucose. Propionyl-CoA is the end product of odd-chain fatty acid metabolism, including most methylated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malonyl-CoA
Malonyl-CoA is a coenzyme A derivative of malonic acid. Functions It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis. Fatty acid biosynthesis Malonyl-CoA provides 2-carbon units to fatty acids and commits them to fatty acid chain synthesis. Malonyl-CoA is formed by carboxylating acetyl-CoA using the enzyme acetyl-CoA carboxylase. One molecule of acetyl-CoA joins with a molecule of bicarbonate,Nelson D, Cox M (2008) ''Lehninger principles of biochemistry''. 5th Ed: p. 806 requiring energy rendered from ATP. Malonyl-CoA is utilised in fatty acid biosynthesis by the enzyme malonyl coenzyme A:acyl carrier protein transacylase (MCAT). MCAT serves to transfer malonate from malonyl-CoA to the terminal thiol of ''holo''-acyl carrier protein (ACP). Polyketide biosynthesis MCAT is also involved in bacterial polyketide biosynthesis. The enzyme MCAT together with an acyl carrier protein (ACP), and a polyketide synthase (PKS) and chain-length f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylmalonyl-CoA
Methylmalonyl-CoA is the thioester consisting of coenzyme A linked to methylmalonic acid. It is an important intermediate in the biosynthesis of succinyl-CoA, which plays an essential role in the tricarboxylic acid cycle (aka the Citric Acid Cycle, or Krebs Cycle). The compound is sometimes referred to as "methylmalyl-CoA". Biosynthesis and metabolism Methylmalonyl-CoA results from the metabolism of fatty acid with an odd number of carbons or from cholesterol side-chains, forming Propionyl-CoA. Propionyl-CoA and bicarbonate are converted to Methylmalonyl-CoA by the enzyme propionyl-CoA Carboxylase. It then is converted into succinyl-CoA by methylmalonyl-CoA mutase (MUT). This reaction is a reversible isomerization. In this way, the compound enters the Citric Acid Cycle. The following diagram demonstrates the aforementioned reaction: Propionyl CoA + Bicarbonate → Methylmalonyl CoA → Succinyl CoA Vitamin B12 Vitamin B12 plays an integral role in this reaction. Coenzyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetyl-CoA
Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production. Coenzyme A (CoASH or CoA) consists of a β-mercaptoethylamine group linked to the vitamin pantothenic acid (B5) through an amide linkage and 3'-phosphorylated ADP. The acetyl group (indicated in blue in the structural diagram on the right) of acetyl-CoA is linked to the sulfhydryl substituent of the β-mercaptoethylamine group. This thioester linkage is a "high energy" bond, which is particularly reactive. Hydrolysis of the thioester bond is exergonic (−31.5 kJ/mol). CoA is acetylated to acetyl-CoA by the breakdown of carbohydrates through glycolysis and by the breakdown of fatty acids through β-oxidation. Acetyl-CoA then enters the citric acid cycle, where the acetyl group is oxidized to carbon dioxide and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyoxylate
Glyoxylic acid or oxoacetic acid is an organic compound. Together with acetic acid, glycolic acid, and oxalic acid, glyoxylic acid is one of the C2 carboxylic acids. It is a colourless solid that occurs naturally and is useful industrially. Structure and nomenclature Although the structure of glyoxylic acid is described as having an aldehyde functional group, the aldehyde is only a minor component of the form most prevalent in some situations. Instead, it often exists as a hydrate or a cyclic dimer. For example, in the presence of water, the carbonyl rapidly converts to a geminal diol (described as the "monohydrate"). The equilibrium constant (''K'') is 300 for the formation of dihydroxyacetic acid at room temperature: : In solution, the monohydrate exists in equilibrium with a hemi acylal dimer form:Georges Mattioda and Yani Christidis “Glyoxylic Acid” Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. : In isolation, the aldehyde structure ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyoxylate
Glyoxylic acid or oxoacetic acid is an organic compound. Together with acetic acid, glycolic acid, and oxalic acid, glyoxylic acid is one of the C2 carboxylic acids. It is a colourless solid that occurs naturally and is useful industrially. Structure and nomenclature Although the structure of glyoxylic acid is described as having an aldehyde functional group, the aldehyde is only a minor component of the form most prevalent in some situations. Instead, it often exists as a hydrate or a cyclic dimer. For example, in the presence of water, the carbonyl rapidly converts to a geminal diol (described as the "monohydrate"). The equilibrium constant (''K'') is 300 for the formation of dihydroxyacetic acid at room temperature: : In solution, the monohydrate exists in equilibrium with a hemi acylal dimer form:Georges Mattioda and Yani Christidis “Glyoxylic Acid” Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. : In isolation, the aldehyde structure ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroflexus
Chloroflexales is an order of bacteria in the class Chloroflexia. Taxonomy The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). * Suborder Roseiflexineae Gupta et al. 2013 ** Family Roseiflexaceae Gupta et al. 2013 Kouleotrichaceae" Mehrshad et al. 2018*** Genus "'' Kouleothrix''" Kohno et al. 2002 *** Genus '' Heliothrix'' Pierson et al. 1986 *** Genus ''Roseiflexus'' Hanada et al. 2002 * Suborder Chloroflexineae Gupta et al. 2013 ** Family Chloroflexaceae Gupta et al. 2013 *** Genus ''Candidatus'' Chloranaerofilum Thiel et al. 2016 *** Genus ''Chloroflexus'' Pierson & Castenholz 1974 ''Chlorocrinis''"">Chlorocrinis.html" ;"title="''Chlorocrinis">''Chlorocrinis''"** Family Oscillochloridaceae Gupta et al. 2013 *** Genus ''Candidatus'' Chloroploca Gorlenko et al. 2014 *** Genus ''Chloronema'' ♪ Dubinina & Gorlenko 1975 *** Genus ''Oscillochloris'' Gorlenko & ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemotrophic
A Chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic ( chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which use photons. Chemotrophs can be either autotrophic or heterotrophic. Chemotrophs can be found in areas where electron donors are present in high concentration, for instance around hydrothermal vents. Chemoautotroph Chemoautotrophs, in addition to deriving energy from chemical reactions, synthesize all necessary organic compounds from carbon dioxide. Chemoautotrophs can use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia or organic sources to produce energy. Most chemoautotrophs are extremophiles, bacteria or archaea that live in hostile environments (such as deep sea vents) and are the primary producers in such ecosystems. Chemoautotrophs generally fall into s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
