|
Fumarate Reductase
Fumarate reductase is the enzyme that converts fumarate to succinate, and is important in microbial metabolism as a part of anaerobic respiration. Succinate + acceptor fumarate + reduced acceptor Fumarate reductases can be divided into two classes depending on the electron acceptor: *Fumarate reductase (quinol) () *:The membrane-bound enzyme covalently linked to flavin cofactors, which is composed of 3 or 4 subunits, transfers electrons from a quinol to fumarate. This class of enzyme is thus involved in the production of ATP by oxidative phosphorylation. *Fumarate reductase (NADH) () *:The enzyme is monomeric and soluble, and can reduce fumarate independently from the electron transport chain An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples th .... Fumarate reductase is absent from all ... [...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] |
Fumaric Acid
Fumaric acid is an organic compound with the formula HO2CCH=CHCO2H. A white solid, fumaric acid occurs widely in nature. It has a fruit-like taste and has been used as a food additive. Its E number is E297. The salts and esters are known as fumarates. Fumarate can also refer to the ion (in solution). Fumaric acid is the trans isomer of butenedioic acid, while maleic acid is the cis isomer. Biosynthesis and occurrence It is produced in eukaryotic organisms from succinate in complex 2 of the electron transport chain via the enzyme succinate dehydrogenase. It is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid. In fumaric acid the carboxylic acid groups are ''trans'' (''E'') and in maleic acid they are ''cis'' (''Z''). Fumaric acid is found in fumitory (''Fumaria officinalis''), bolete mushrooms (specifically ''Boletus fomentarius var. pseudo-igniarius''), lichen, and Iceland moss. Fumarate is an intermediate in the citric acid cycle used b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinic Acid
Succinic acid () is a dicarboxylic acid with the chemical formula (CH2)2(CO2H)2. The name derives from Latin ''succinum'', meaning amber. In living organisms, succinic acid takes the form of an anion, succinate, which has multiple biological roles as a metabolic intermediate being converted into fumarate by the enzyme succinate dehydrogenase in complex 2 of the electron transport chain which is involved in making ATP, and as a signaling molecule reflecting the cellular metabolic state. It is marketed as food additive E363. Succinate is generated in mitochondria via the tricarboxylic acid cycle (TCA). Succinate can exit the mitochondrial matrix and function in the cytoplasm as well as the extracellular space, changing gene expression patterns, modulating epigenetic landscape or demonstrating hormone-like signaling. As such, succinate links cellular metabolism, especially ATP formation, to the regulation of cellular function. Dysregulation of succinate synthesis, and therefore A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial Metabolism
Microbial metabolism is the means by which a microbe obtains the energy and nutrients (e.g. carbon) it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles. Types All microbial metabolisms can be arranged according to three principles: 1. How the organism obtains carbon for synthesizing cell mass:Morris, J. et al. (2019). "Biology: How Life Works", 3rd edition, W. H. Freeman. * autotrophic – carbon is obtained from carbon dioxide () * heterotrophic – carbon is obtained from organic compounds * mixotrophic – carbon is obtained from both organic compounds and by fixing carbon dioxide 2. How the organism obtains reducing e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaerobic Respiration
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2). Although oxygen is not the final electron acceptor, the process still uses a respiratory electron transport chain. In aerobic organisms undergoing respiration, electrons are shuttled to an electron transport chain, and the final electron acceptor is oxygen. Molecular oxygen is an excellent electron acceptor. Anaerobes instead use less-oxidizing substances such as nitrate (), fumarate (), sulfate (), or elemental sulfur (S). These terminal electron acceptors have smaller reduction potentials than O2. Less energy per oxidized molecule is released. Therefore, anaerobic respiration is less efficient than aerobic. As compared with fermentation Anaerobic cellular respiration and fermentation generate ATP in very different ways, and the terms should not be treated as synonyms. Cellular respiration (both aerobic and anaerobic) uses highly reduced chemical compounds such as NADH and FADH2 ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumarate Reductase (quinol)
Fumarate reductase (quinol) (, ''QFR,'' ''FRD'', ''menaquinol-fumarate oxidoreductase, quinol:fumarate reductase'') is an enzyme with systematic name ''succinate:quinone oxidoreductase''. This enzyme catalyzes the following chemical reaction: : fumarate + quinol \longrightarrow succinate + quinone Fumarate reductase (QFR) is a key enzyme induced by anaerobic growth of bacteria. By partaking in fumarate respiration, fumarate reductase performs the last step in the microbial anaerobic respiration. It is a membrane bound protein capable of oxidizing a quinone and passing the released electrons to an awaiting fumarate to be reduced. It is activated and synthesized under low oxygen conditions, when aerobic respiration cannot be performed and the cell must perform anaerobic respiration to grow. This reaction is opposite to the reaction that is catalyzed by the related complex II of the respiratory chain (succinate dehydrogenase (SQR)). Enzyme Structure To date, a number of QFR e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumarate Reductase (NADH)
In enzymology, a fumarate reductase (NADH) () is an enzyme that catalyzes the chemical reaction :succinate + NAD+ \rightleftharpoons fumarate + NADH + H+ Thus, the two substrates of this enzyme are succinate and NAD+, whereas its three products are fumarate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is succinate:NAD+ oxidoreductase. Other names in common use include NADH-fumarate reductase, NADH-dependent fumarate reductase, and fumarate reductase (NADH). References * EC 1.3.1 NADH-dependent enzymes Enzymes of unknown structure {{1.3-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Transport Chain
An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. The electrons that transferred from NADH and FADH2 to the ETC involves 4 multi-subunit large enzymes complexes and 2 mobile electron carriers. Many of the enzymes in the electron transport chain are membrane-bound. The flow of electrons through the electron transport chain is an exergonic process. The energy from the redox reactions creates an electrochemical proton gradient that drives the synthesis of adenosine triphosphate (ATP). In aerobic respiration, the flow of electrons terminates with molecular oxygen as the final electron acceptor. In anaerobic respiration, other electron acceptors are used, such as sulfate. In an electron transport chain, the redo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Anaerobic Respiration")
