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Gab Operon
The ''gab'' operon is responsible for the conversion of γ-aminobutyrate (GABA) to succinate. The ''gab'' operon comprises three structural genes – ''gabD'', ''gabT'' and ''gabP'' – that encode for a succinate semialdehyde dehydrogenase, GABA transaminase and a GABA permease respectively. There is a regulatory gene ''csiR'', downstream of the operon, that codes for a putative transcriptional repressor and is activated when nitrogen is limiting. The ''gab'' operon has been characterized in ''Escherichia coli'' and significant homologies for the enzymes have been found in organisms such as ''Saccharomyces cerevisiae'', rats and humans. Limited nitrogen conditions activate the ''gab'' genes. The enzymes produced by these genes convert GABA to succinate, which then enters the TCA cycle, to be used as a source of energy. The ''gab'' operon is also known to contribute to polyamine homeostasis during nitrogen-limited growth and to maintain high internal glutamate concentrations unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gab Reaction
Gab or GAB may refer to: * Gáb, a cuneiform sign * Gab (social network), an American social networking platform * "Gab" (song), an Occitan boasting song of the Middle Ages * Gab, Iran, a village in Hormozgan Province * Games and Amusements Board, a Philippine sports and gambling regulatory government agency * Georgia Academy for the Blind * German American Bund, a German-American pro-Nazi organization (1936–1941) * Government Accountability Board, a defunct (since 2016) Wisconsin political regulatory institution * The Great American Bash, a professional wrestling event * Great Artesian Basin, in Australia * Great Australian Bight, an open bay * Greater Atlantic Bank, a defunct American community bank See also * Gabb (other) * Gabs (other) Gabs or GABS may refer to: *Golden Arrow Bus Services, a bus company in Cape Town, South Africa *Gaborone, the capital and largest city of the Botswana nicknamed Gabs *Great Australasian Beer SpecTAPular, a craft beer festi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinate
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] |
Operon
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product. The result of this is that the genes contained in the operon are either expressed together or not at all. Several genes must be ''co-transcribed'' to define an operon. Originally, operons were thought to exist solely in prokaryotes (which includes organelles like plastids that are derived from bacteria), but since the discovery of the first operons in eukaryotes in the early 1990s, more evidence has arisen to suggest they are more common than previously assumed. In general, expression of prokaryotic operons leads to the generation of polycistronic mRNAs, while eukaryotic operons lead to monocistronic mR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-aminobutyrate Transaminase
In enzymology, 4-aminobutyrate transaminase (), also called GABA transaminase or 4-aminobutyrate aminotransferase, or GABA-T, is an enzyme that catalysis, catalyzes the chemical reaction: :4-aminobutanoate + 2-oxoglutarate \rightleftharpoons succinate semialdehyde + L-glutamate Thus, the two substrate (biochemistry), substrates of this enzyme are 4-aminobutanoate (GABA) and 2-oxoglutarate. The two product (chemistry), products are succinate semialdehyde and L-glutamate. This enzyme belongs to the family of transferases, specifically the transaminases, which transfer nitrogenous groups. The List of enzymes, systematic name of this enzyme class is 4-aminobutanoate:2-oxoglutarate aminotransferase. This enzyme participates in 5 metabolic pathways: alanine and aspartate metabolism, glutamate metabolism, beta-alanine metabolism, propanoate metabolism, and butyric acid, butanoate metabolism. It employs one cofactor (biochemistry), cofactor, pyridoxal phosphate. This enzyme is found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinate-semialdehyde Dehydrogenase
In enzymology, a succinate-semialdehyde dehydrogenase (SSADH) () is an enzyme that catalyzes the chemical reaction :succinate semialdehyde + NAD+ + H2O succinate + NADH + 2 H+ The 3 substrates of this enzyme are succinate semialdehyde, NAD+, and H2O, whereas its 3 products are succinate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is succinate-semialdehyde:NAD+ oxidoreductase. Other names in common use include succinate semialdehyde dehydrogenase, succinic semialdehyde dehydrogenase, succinyl semialdehyde dehydrogenase, and succinate semialdehyde:NAD+ oxidoreductase. This enzyme participates in glutamate and butyrate metabolism. Succinate-semialdehyde dehydrogenase is found in organisms ranging across the tree of life from bacteria to humans. It is important in the degradation of γ-aminobutyric acid in humans, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citric Acid Cycle
The citric acid cycle (CAC)—also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. The Krebs cycle is used by organisms that respire (as opposed to organisms that ferment) to generate energy, either by anaerobic respiration or aerobic respiration. In addition, the cycle provides precursors of certain amino acids, as well as the reducing agent NADH, that are used in numerous other reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest components of metabolism and may have originated abiogenically. Even though it is branded as a 'cycle', it is not necessary for metabolites to follow only one specific route; at least three alternative segments of the citric acid cycle have been recognized. The name of this metabolic pathway is derived from the citric acid (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyamines
A polyamine is an organic compound having more than two amino groups. Alkyl polyamines occur naturally, but some are synthetic. Alkylpolyamines are colorless, hygroscopic, and water soluble. Near neutral pH, they exist as the ammonium derivatives. Most aromatic polyamines are crystalline solids at room temperature. Natural polyamines Low-molecular-weight linear polyamines are found in all forms of life. The principal examples are the triamine spermidine and the tetraamine spermine. They are structurally and biosynthetically related to the diamines putrescine and cadaverine. Polyamine metabolism is regulated by the activity of the enzyme ornithine decarboxylase (ODC). Polyamines are found in high concentrations in the mammalian brain. File:Spermidine-2D-skeletal.svg, spermidine File:Spermine.svg, spermine Synthetic polyamines Several synthetic polyamines are used in chemical industry and the research laboratory. They are mainly of interest as additives to motor oil and as co-re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Putrescine
Putrescine is an organic compound with the formula (CH2)4(NH2)2. It is a colorless solid that melts near room temperature. It is classified as a diamine. Together with cadaverine, it is largely responsible for the foul odor of putrefying flesh, but also contributes to other unpleasant odors. Production Putrescine is produced on an industrial scale by the hydrogenation of succinonitrile. Biotechnological production of putrescine from renewable feedstock has been investigated. A metabolically engineered strain of ''Escherichia coli'' that produces putrescine at high concentrations in glucose mineral salts medium has been described. Biochemistry Spermidine synthase uses putrescine and ''S''-adenosylmethioninamine (decarboxylated ''S''-adenosyl methionine) to produce spermidine. Spermidine in turn is combined with another ''S''-adenosylmethioninamine and gets converted to spermine. Putrescine is synthesized in small quantities by healthy living cells by the action of ornithi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABA-ergic neurons. Its molecular formula is . Glutamic acid exists in three optically isomeric forms; the dextrorotatory -form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971. Its molecular structure could be idealized as HOOC−CH()−()2−COOH, with two carboxyl groups −COOH and one amino group −. However, in the solid state and mildly acidic water solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RpoS
The gene ''rpoS'' (RNA polymerase, sigma S, also called katF) encodes the sigma factor ''sigma-38'' (σ38, or RpoS), a 37.8 kD protein in ''Escherichia coli''. Sigma factors are proteins that regulate transcription in bacteria. Sigma factors can be activated in response to different environmental conditions. ''rpoS'' is transcribed in late exponential phase, and RpoS is the primary regulator of stationary phase genes. RpoS is a central regulator of the general stress response and operates in both a retroactive and a proactive manner: it not only allows the cell to survive environmental challenges, but it also prepares the cell for subsequent stresses (cross-protection). The transcriptional regulator CsgD is central to biofilm formation, controlling the expression of the curli structural and export proteins, and the diguanylate cyclase, adrA, which indirectly activates cellulose production. The ''rpoS'' gene most likely originated in the gammaproteobacteria. Environmental sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAMP Receptor Protein
cAMP receptor protein (CRP; also known as catabolite activator protein, CAP) is a regulatory protein in bacteria. CRP protein binds cAMP, which causes a conformational change that allows CRP to bind tightly to a specific DNA site in the promoters of the genes it controls. CRP then activates transcription through direct protein–protein interactions with RNA polymerase. The genes regulated by CRP are mostly involved in energy metabolism, such as galactose, citrate, or the PEP group translocation system. In '' Escherichia coli'', cyclic AMP receptor protein (CRP) can regulate the transcription of more than 100 genes. The signal to activate CRP is the binding of cyclic AMP. Binding of cAMP to CRP leads to a long-distance signal transduction from the N-terminal cAMP-binding domain to the C-terminal domain of the protein, which is responsible for interaction with specific sequences of DNA. At "Class I" CRP-dependent promoters, CRP binds to a DNA site located upstream of core ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
