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Enolase
Phosphopyruvate hydratase, usually known as enolase, is a metalloenzyme () that catalyses the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), the ninth and penultimate step of glycolysis. The chemical reaction is: :2-phospho-D-glycerate \rightleftharpoons phosphoenolpyruvate + H2O Phosphopyruvate hydratase belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme is 2-phospho-D-glycerate hydro-lyase (phosphoenolpyruvate-forming). The reaction is reversible, depending on environmental concentrations of substrates. The optimum pH for the human enzyme is 6.5. Enolase is present in all tissues and organisms capable of glycolysis or fermentation. The enzyme was discovered by Lohmann and Meyerhof in 1934, and has since been isolated from a variety of sources including human muscle and erythrocytes. In humans, deficiency of ENO1 is linked to hereditary haemolytic anemia, while ENO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enolase Mechanism2
Phosphopyruvate hydratase, usually known as enolase, is a metalloenzyme () that catalyses the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), the ninth and penultimate step of glycolysis. The chemical reaction is: :2-phospho-D-glycerate \rightleftharpoons phosphoenolpyruvate + H2O Phosphopyruvate hydratase belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme is 2-phospho-D-glycerate hydro-lyase (phosphoenolpyruvate-forming). The reaction is reversible, depending on environmental concentrations of substrates. The optimum pH for the human enzyme is 6.5. Enolase is present in all tissues and organisms capable of glycolysis or fermentation. The enzyme was discovered by Lohmann and Meyerhof in 1934, and has since been isolated from a variety of sources including human muscle and erythrocytes. In humans, deficiency of ENO1 is linked to hereditary haemolytic anemia, while ENO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enolase Deficiency
Enolase Deficiency is a rare genetic disorder of glucose metabolism. Partial deficiencies have been observed in several caucasian families. The deficiency is transmitted through an autosomal dominant inheritance pattern. The gene for Enolase 1 has been localized to Chromosome 1 in humans. Enolase deficiency, like other glycolytic enzyme deficiences, usually manifests in red blood cells as they rely entirely on anaerobic glycolysis. Enolase deficiency is associated with a spherocytic phenotype and can result in hemolytic anemia, which is responsible for the clinical signs of Enolase deficiency. Symptoms Symptoms of enolase deficiency include exercise-induced myalgia and generalized muscle weakness and fatigability, both with onset in adulthood. Symptoms also include muscle pain without cramps, and decreased ability to sustain long term exercise. Causes Genetics is found to be the cause of enolase deficiency. The individual in the first known case of this deficiency was h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Enolase
Enolase 1 (ENO1), more commonly known as alpha-enolase, is a glycolytic enzyme expressed in most tissues, one of the isozymes of enolase. Each isoenzyme is a homodimer composed of 2 alpha, 2 gamma, or 2 beta subunits, and functions as a glycolytic enzyme. Alpha-enolase, in addition, functions as a structural lens protein (tau-crystallin) in the monomeric form. Alternative splicing of this gene results in a shorter isoform that has been shown to bind to the ''c-myc'' promoter and function as a tumor suppressor. Several pseudogenes have been identified, including one on the long arm of chromosome 1. Alpha-enolase has also been identified as an autoantigen in Hashimoto encephalopathy. Structure ENO1 is one of three enolase isoforms, the other two being ENO2 (ENO-γ) and ENO3 (ENO-β). Each isoform is a protein subunit that can hetero- or homodimerize to form αα, αβ, αγ, ββ, and γγ dimers. The ''ENO1'' gene spans 18 kb and lacks a TATA box while possessing multiple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-enolase
Enolase 1 (ENO1), more commonly known as alpha-enolase, is a glycolytic enzyme expressed in most tissues, one of the isozymes of enolase. Each isoenzyme is a homodimer composed of 2 alpha, 2 gamma, or 2 beta subunits, and functions as a glycolytic enzyme. Alpha-enolase, in addition, functions as a structural lens protein (tau-crystallin) in the monomeric form. Alternative splicing of this gene results in a shorter isoform that has been shown to bind to the ''c-myc'' promoter and function as a tumor suppressor. Several pseudogenes have been identified, including one on the long arm of chromosome 1. Alpha-enolase has also been identified as an autoantigen in Hashimoto encephalopathy. Structure ENO1 is one of three enolase isoforms, the other two being ENO2 (ENO-γ) and ENO3 (ENO-β). Each isoform is a protein subunit that can hetero- or homodimerize to form αα, αβ, αγ, ββ, and γγ dimers. The ''ENO1'' gene spans 18 kb and lacks a TATA box while possessing multipl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enolase Superfamily
The enolase superfamily is a superfamily of enzymes, members of which catalyse a range of reactions. The enolase superfamily includes enzymes that catalyse a wide variety of reactions and performing diverse roles in metabolism. However, the reactions catalysed share the common chemical step of abstraction of a proton from a carbon adjacent to a carboxylic acid and a requirement of a divalent metal ion. This diversity of functions is in contrast to many families of enzymes whose members catalyse similar chemical reactions on different substrates. Members * Enolase * Mandelate racemase (MR) * Muconate lactonizing enzyme (MLE) The primary sequences of MR and MLE, approximately 25% identical Two things are identical if they are the same, see Identity (philosophy). Identical may also refer to: * ''Identical'' (Hopkins novel), a 2008 young adult novel by Ellen Hopkins * ''Identical'' (Turow novel), a 2013 legal drama novel by Scott T ..., are related but significantly dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enolase 2
Gamma-enolase, also known as enolase 2 (ENO2) or neuron specific enolase (NSE), is an enzyme that in humans is encoded by the ''ENO2'' gene. Gamma-enolase is a phosphopyruvate hydratase. Gamma-enolase is one of the three enolase isoenzymes found in mammals. This isoenzyme, a homodimer, is found in mature neurons and cells of neuronal origin. A switch from alpha enolase to gamma enolase occurs in neural tissue during development in rats and primates. Interactive pathway map Utility Detection of NSE with antibodies can be used to identify neuronal cells and cells with neuroendocrine differentiation. NSE is produced by small-cell carcinomas, which are neuroendocrine Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules ( hormones) into the blood. In this way they b ... in origin. NSE is therefore a useful tumor marker for distinguis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ENO2
Gamma-enolase, also known as enolase 2 (ENO2) or neuron specific enolase (NSE), is an enzyme that in humans is encoded by the ''ENO2'' gene. Gamma-enolase is a phosphopyruvate hydratase. Gamma-enolase is one of the three enolase isoenzymes found in mammals. This isoenzyme, a homodimer, is found in mature neurons and cells of neuronal origin. A switch from alpha enolase to gamma enolase occurs in neural tissue during development in rats and primates. Interactive pathway map Utility Detection of NSE with antibodies can be used to identify neuronal cells and cells with neuroendocrine differentiation. NSE is produced by small-cell carcinomas, which are neuroendocrine Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules (hormones) into the blood. In this way they bri ... in origin. NSE is therefore a useful tumor marker for distingui ... [...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] |
ENO3
Enolase 3 (ENO3), more commonly known as beta-enolase (ENO-β), is an enzyme that in humans is encoded by the ''ENO3'' gene. This gene encodes one of the three enolase isoenzymes found in mammals. This isoenzyme is found in skeletal muscle cells in the adult where it may play a role in muscle development and regeneration. A switch from alpha enolase to beta enolase occurs in muscle tissue during development in rodents. Mutations in this gene have been associated with glycogen storage disease. Alternatively spliced transcript variants encoding different isoforms have been described. rovided by RefSeq, Jul 2010ref name="entrez"> Structure ENO3 is one of three enolase isoforms, the other two being ENO1 (ENO-α) and ENO2 (ENO-γ). Each isoform is a protein subunit that can form hetero- or homodimers of the following combinations: αα, αβ, αγ, ββ, and γγ. Gene The ''ENO3'' gene spans 6 kb and contains 12 exons, though the first exon is an untranslated region and, thus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoenolpyruvate
Phosphoenolpyruvate (2-phosphoenolpyruvate, PEP) is the ester derived from the enol of pyruvate and phosphate. It exists as an anion. PEP is an important intermediate in biochemistry. It has the highest-energy phosphate bond found (−61.9 kJ/mol) in organisms, and is involved in glycolysis and gluconeogenesis. In plants, it is also involved in the biosynthesis of various aromatic compounds, and in carbon fixation; in bacteria, it is also used as the source of energy for the phosphotransferase system. In glycolysis PEP is formed by the action of the enzyme enolase on 2-phosphoglyceric acid. Metabolism of PEP to pyruvic acid by pyruvate kinase (PK) generates adenosine triphosphate (ATP) via substrate-level phosphorylation. ATP is one of the major currencies of chemical energy within cells. In gluconeogenesis PEP is formed from the decarboxylation of oxaloacetate and hydrolysis of one guanosine triphosphate molecule. This reaction is catalyzed by the enzyme pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, it has now been shown in longer-term studies to be essential for adults also. It is encoded by the codons CAU and CAC. Histidine was first isolated by Albrecht Kossel and Sven Gustaf Hedin in 1896. It is also a precursor to histamine, a vital inflammatory agent in immune responses. The acyl radical is histidyl. Properties of the imidazole side chain The conjugate acid (protonated form) of the imidazole side chain in histidine has a p''K''a of approximately 6.0. Thus, below a pH of 6, the imidazole ring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E1cb
The E1cB elimination reaction is a type of elimination reaction which occurs under basic conditions, where the hydrogen to be removed is relatively acidic, while the leaving group (such as -OH or -OR) is a relatively poor one. Usually a moderate to strong base is present. E1cB is a two-step process, the first step of which may or may not be reversible. First, a base abstracts the relatively acidic proton to generate a stabilized anion. The lone pair of electrons on the anion then moves to the neighboring atom, thus expelling the leaving group and forming double or triple bond. The name of the mechanism - E1cB - stands for Elimination Unimolecular conjugate Base. ''Elimination'' refers to the fact that the mechanism is an elimination reaction and will lose two substituents. ''Unimolecular'' refers to the fact that the rate-determining step of this reaction only involves one molecular entity. Finally, ''conjugate base'' refers to the formation of the carbanion intermediate, which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
