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Aldolase
Fructose-bisphosphate aldolase (), often just aldolase, is an enzyme catalyzing a reversible reaction that splits the aldol, fructose 1,6-bisphosphate, into the triose phosphates dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (G3P). Aldolase can also produce DHAP from other (3S,4R)-ketose 1-phosphates such as fructose 1-phosphate and sedoheptulose 1,7-bisphosphate. Gluconeogenesis and the Calvin cycle, which are anabolic pathways, use the reverse reaction. Glycolysis, a catabolic pathway, uses the forward reaction. Aldolase is divided into two classes by mechanism. The word aldolase also refers, more generally, to an enzyme that performs an aldol reaction (creating an aldol) or its reverse (cleaving an aldol), such as Sialic acid aldolase, which forms sialic acid. See the list of aldolases. Mechanism and structure Class I proteins form a protonated Schiff base intermediate linking a highly conserved active site lysine with the DHAP carbonyl carbon. Addit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Aldolases
Unqualified, aldolase usually refers to the enzyme fructose-bisphosphate aldolase. Aldolase may also refer to: Proteins serving as fructose-bisphosphate aldolase * Aldolase A * Aldolase B * Aldolase C Other enzymes called "aldolases" * 17a-hydroxyprogesterone aldolase * 2-dehydro-3-deoxy-6-phosphogalactonate aldolase * 2-dehydro-3-deoxy-D-pentonate aldolase * 2-dehydro-3-deoxyglucarate aldolase * 2-dehydro-3-deoxy-L-pentonate aldolase * 2-dehydro-3-deoxy-phosphogluconate aldolase * 2-dehydropantoate aldolase * 3-deoxy-D-manno-octulosonate aldolase * 4-(2-carboxyphenyl)-2-oxobut-3-enoate aldolase * 5-dehydro-2-deoxyphosphogluconate aldolase * Benzoin aldolase * Deoxyribose-phosphate aldolase * Dihydroneopterin aldolase * Dimethylaniline-N-oxide aldolase * Ketotetrose-phosphate aldolase * Lactate aldolase * L-fuculose-phosphate aldolase * Phenylserine aldolase * Rhamnulose-1-phosphate aldolase * Sphinganine-1-phosphate aldolase * Tagatose-bisphosphate aldolase * Threonine aldolas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-acetylneuraminate Lyase
The enzyme ''N''-acetylneuraminate lyase () catalyzes the chemical reaction :''N''-acetylneuraminate \rightleftharpoons N-acetyl-D-mannosamine + pyruvate This enzyme belongs to the family of lyases, specifically the oxo-acid-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is N-acetylneuraminate pyruvate-lyase (N-acetyl-D-mannosamine-forming). Other names in common use include N-acetylneuraminic acid aldolase, acetylneuraminate lyase, sialic aldolase, sialic acid aldolase, sialate lyase, N-acetylneuraminic aldolase, neuraminic aldolase, N-acetylneuraminate aldolase, neuraminic acid aldolase, N-acetylneuraminic acid aldolase, neuraminate aldolase, N-acetylneuraminic lyase, N-acetylneuraminic acid lyase, NPL, NALase, NANA lyase, acetylneuraminate pyruvate-lyase, and N-acetylneuraminate pyruvate-lyase. This enzyme participates in aminosugars metabolism. Structural studies As of late 2007, 10 structures A structure is an arrangement and organiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycolysis
Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). Glycolysis is a sequence of ten reactions catalyzed by enzymes. Glycolysis is a metabolic pathway that does not require oxygen (In anaerobic conditions pyruvate is converted to lactic acid). The wide occurrence of glycolysis in other species indicates that it is an ancient metabolic pathway. Indeed, the reactions that make up glycolysis and its parallel pathway, the pentose phosphate pathway, occur in the oxygen-free conditions of the Archean oceans, also in the absence of enzymes, catalyzed by metal. In most organisms, glycolysis occurs in the liquid part of cells, the cytosol. The most common type of glycolysis is the ''Embden–Meyerhof–Parnas (EMP) pathway'', which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldol Reaction
The aldol reaction is a means of forming carbon–carbon bonds in organic chemistry. Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles-Adolphe Wurtz in 1872, the reaction combines two carbonyl compounds (the original experiments used aldehydes) to form a new β-hydroxy carbonyl compound. These products are known as ''aldols'', from the ''ald''ehyde + alcoh''ol'', a structural motif seen in many of the products. Aldol structural units are found in many important molecules, whether naturally occurring or synthetic. For example, the aldol reaction has been used in the large-scale production of the commodity chemical pentaerythritol and the synthesis of the heart disease drug Lipitor (atorvastatin, calcium salt). The aldol reaction unites two relatively simple molecules into a more complex one. Increased complexity arises because up to two new stereogenic centers (on the Alpha carbon, α- and β-carbon of the aldol adduct, mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyceraldehyde 3-phosphate
Glyceraldehyde 3-phosphate, also known as triose phosphate or 3-phosphoglyceraldehyde and abbreviated as G3P, GA3P, GADP, GAP, TP, GALP or PGAL, is a metabolite that occurs as an intermediate in several central pathways of all organisms.Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. . With the chemical formula H(O)CCH(OH)CH2OPO32-, this anion is a monophosphate ester of glyceraldehyde. An intermediate in both glycolysis and gluconeogenesis Formation D-glyceraldehyde 3-phosphate is formed from the following three compounds in reversible reactions: *Fructose-1,6-bisphosphate ( F1,6BP), catalyzed by aldolase. ''The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.'' *Dihydroxyacetone phosphate ( DHAP), catalyzed by triose phosphate isomerase. *1,3-bisphosphoglycerate ( 1,3BPG), catalyzed by glyceraldehyde 3-phosphate dehydrogenase. As a substra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tagatose-bisphosphate Aldolase
The enzyme tagatose-bisphosphate aldolase () catalysis, catalyzes the chemical reaction :D-tagatose 1,6-bisphosphate \rightleftharpoons glycerone phosphateCommonly known as dihydroxyacetone phosphate. + Dglyceraldehyde 3-phosphate This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. The List of enzymes, systematic name of this enzyme class is D-tagatose 1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase (glycerone-phosphate-forming). This enzyme is also called D-tagatose-1,6-bisphosphate triosephosphate lyase. This enzyme participates in galactose metabolism. Structural studies As of late 2007, only one tertiary structure, structure has been solved for this class of enzymes, with the Protein Data Bank, PDB accession code . References * * EC 4.1.2 Enzymes of known structure {{4.1-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fructose 1-phosphate
Fructose-1-phosphate is a derivative of fructose. It is generated mainly by hepatic fructokinase but is also generated in smaller amounts in the small intestinal mucosa and proximal epithelium of the renal tubule. It is an important intermediate of glucose metabolism. Because fructokinase has a high Vmax fructose entering cells is quickly phosphorylated to fructose 1-phosphate."Marks A. Basic Medical Biochemistry: a clinical approach, 3rd ed. p.540 In this form it is usually accumulated in the liver until it undergoes further conversion by aldolase B (the rate limiting enzyme of fructose metabolism). Aldolase B converts it into glyceraldehyde and dihydroxyacetone phosphate (DHAP). Glyceraldehyde is then phosphorylated by triose kinase to glyceraldehyde 3-phosphate. Metabolism of fructose thus essentially results in intermediates of glycolysis. This means that fructose has the same fate as glucose after it gets metabolised. The final product of glycolysis (pyruvate) may then undergo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fructose 1,6-bisphosphate
Fructose 1,6-bisphosphate, also known as Harden-Young ester, is fructose sugar phosphorylated on carbons 1 and 6 (i.e., is a fructosephosphate). The β-D-form of this compound is common in cells. Upon entering the cell, most glucose and fructose is converted to fructose 1,6-bisphosphate. In glycolysis Fructose 1,6-bisphosphate lies within the glycolysis metabolic pathway and is produced by phosphorylation of fructose 6-phosphate. It is, in turn, broken down into two compounds: glyceraldehyde 3-phosphate and dihydroxyacetone phosphate. It is an allosteric activator of pyruvate kinase through distinct interactions of binding and allostery at the enzyme's catalytic site ''The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.'' Isomerism Fructose 1,6-bisphosphate has only one biologically active isomer, the β-D-form. There are many other isomers, analogous to those of fructose. Iron chelation Fructos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sialic Acid
Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone. The term "sialic acid" (from the Greek for saliva, - ''síalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this group is ''N''-acetylneuraminic acid (Neu5Ac or NANA) found in animals and some prokaryotes. Sialic acids are found widely distributed in animal tissues and related forms are found to a lesser extent in other organisms like in some micro-algae, bacteria and archaea. Sialic acids are commonly part of glycoproteins, glycolipids or gangliosides, where they decorate the end of sugar chains at the surface of cells or soluble proteins. However, sialic acids have been also observed in ''Drosophila'' embryos and other insects. Generally, plants seem not to contain or display sialic acids. In humans the brain has the highest sialic acid content, where these acids play an important role in neural transmission and ganglioside structure in synaptogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroxyacetone Phosphate
Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCH2C(O)CH2OPO32-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis.Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. . It is the phosphate ester of dihydroxyacetone. Role in glycolysis Dihydroxyacetone phosphate lies in the glycolysis metabolic pathway, and is one of the two products of breakdown of fructose 1,6-bisphosphate, along with glyceraldehyde 3-phosphate. It is rapidly and reversibly isomerised to glyceraldehyde 3-phosphate. ''The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.'' Role in other pathways In the Calvin cycle, DHAP is one of the products of the sixfold reduction of 1,3-bisphosphoglycerate by NADPH. It is also used in the synthesis of sedoheptulose 1,7-bisph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calvin Cycle
The Calvin cycle, light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle of photosynthesis is a series of chemical reactions that convert carbon dioxide and hydrogen-carrier compounds into glucose. The Calvin cycle is present in all photosynthetic eukaryotes and also many photosynthetic bacteria. In plants, these reactions occur in the stroma, the fluid-filled region of a chloroplast outside the thylakoid membranes. These reactions take the products ( ATP and NADPH) of light-dependent reactions and perform further chemical processes on them. The Calvin cycle uses the chemical energy of ATP and reducing power of NADPH from the light dependent reactions to produce sugars for the plant to use. These substrates are used in a series of reduction-oxidation reactions to produce sugars in a step-wise process; there is no direct reaction that converts several molecules of to a sugar. There are three phases to the light-independ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Site
In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site). Although the active site occupies only ~10–20% of the volume of an enzyme, it is the most important part as it directly catalyzes the chemical reaction. It usually consists of three to four amino acids, while other amino acids within the protein are required to maintain the tertiary structure of the enzymes. Each active site is evolved to be optimised to bind a particular substrate and catalyse a particular reaction, resulting in high specificity. This specificity is determined by the arrangement of amino acids within the active site and the structure of the substrates. Sometimes enzymes also need to bind with some cofactors to fulfil their function. The active si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
