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42-445: GCG may refer to: Biochemistry GCG, a codon for the amino acid alanine Gallocatechin gallate , a flavonol Proglucagon , a protein GCG (General Computer Group) was collection of programs for the analysis of gene and protein sequences, now defunct Medical Ghost cell glaucoma Other Gallantry Cross, Gold of

84-414: A bidentate ligand for many metal ions, forming amino acid complexes . A typical complex is Cu(glycinate) 2 , i.e. Cu(H 2 NCH 2 CO 2 ) 2 , which exists both in cis and trans isomers. With acid chlorides, glycine converts to the amidocarboxylic acid, such as hippuric acid and acetylglycine . With nitrous acid , one obtains glycolic acid ( van Slyke determination ). With methyl iodide ,

126-403: A key role in glucose–alanine cycle between tissues and liver. In muscle and other tissues that degrade amino acids for fuel, amino groups are collected in the form of glutamate by transamination . Glutamate can then transfer its amino group to pyruvate , a product of muscle glycolysis , through the action of alanine aminotransferase , forming alanine and α-ketoglutarate . The alanine enters

168-402: A library of genes, each of which has a point mutation at a different position in the area of interest, sometimes even every position in the whole gene: this is called "scanning mutagenesis". The simplest method, and the first to have been used, is so-called alanine scanning , where every position in turn is mutated to alanine. Hydrogenation of alanine gives the amino alcohol alaninol , which

210-629: A student of the German chemist Justus von Liebig , proposed the name "glycocoll"; however, the Swedish chemist Berzelius suggested the simpler current name a year later. The name comes from the Greek word γλυκύς "sweet tasting" (which is also related to the prefixes glyco- and gluco- , as in glycoprotein and glucose ). In 1858, the French chemist Auguste Cahours determined that glycine

252-520: Is a strong antagonist at ionotropic glycine receptors, whereas bicuculline is a weak one. Glycine is a required co-agonist along with glutamate for NMDA receptors . In contrast to the inhibitory role of glycine in the spinal cord, this behaviour is facilitated at the ( NMDA ) glutamatergic receptors which are excitatory. The LD 50 of glycine is 7930 mg/kg in rats (oral), and it usually causes death by hyperexcitability. Glycine conjugation pathway has not been fully investigated. Glycine

294-488: Is a useful chiral building block. The deamination of an alanine molecule produces the free radical CH 3 C HCO 2 . Deamination can be induced in solid or aqueous alanine by radiation that causes homolytic cleavage of the carbon–nitrogen bond. This property of alanine is used in dosimetric measurements in radiotherapy . When normal alanine is irradiated, the radiation causes certain alanine molecules to become free radicals, and, as these radicals are stable,

336-459: Is also used to remove protein-labeling antibodies from Western blot membranes to enable the probing of numerous proteins of interest from SDS-PAGE gel. This allows more data to be drawn from the same specimen, increasing the reliability of the data, reducing the amount of sample processing, and number of samples required. This process is known as stripping. The presence of glycine outside the Earth

378-420: Is an aliphatic amino acid, because the side-chain connected to the α-carbon atom is a methyl group (-CH 3 ). Alanine is the simplest α-amino acid after glycine . The methyl side-chain of alanine is non-reactive and is therefore hardly ever directly involved in protein function. Alanine is a nonessential amino acid , meaning it can be manufactured by the human body, and does not need to be obtained through

420-535: Is an intermediate in the synthesis of a variety of chemical products. It is used in the manufacture of the herbicides glyphosate , iprodione , glyphosine, imiprothrin , and eglinazine. It is used as an intermediate of antibiotics such as thiamphenicol . Glycine is a significant component of some solutions used in the SDS-PAGE method of protein analysis. It serves as a buffering agent, maintaining pH and preventing sample damage during electrophoresis. Glycine

462-525: Is different from Wikidata All article disambiguation pages All disambiguation pages Alanine The L - isomer of alanine ( left-handed ) is the one that is incorporated into proteins. L -alanine is second only to L -leucine in rate of occurrence, accounting for 7.8% of the primary structure in a sample of 1,150 proteins . The right-handed form, D -alanine, occurs in peptides in some bacterial cell walls (in peptidoglycan ) and in some peptide antibiotics , and occurs in

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504-452: Is it acts as a precursor to proteins . Most proteins incorporate only small quantities of glycine, a notable exception being collagen , which contains about 35% glycine due to its periodically repeated role in the formation of collagen's helix structure in conjunction with hydroxyproline . In the genetic code , glycine is coded by all codons starting with GG, namely GGU, GGC, GGA and GGG. In higher eukaryotes , δ-aminolevulinic acid ,

546-400: Is rather limited to those alanine derivatives that are suitable for building α-helix or β-sheet secondary structural elements. Dominant secondary structures in life as we know it are α-helices and β-sheets and most canonical amino acids can be regarded as chemical derivatives of alanine. Therefore, most canonical amino acids in proteins can be exchanged with alanine by point mutations while

588-530: Is sold at a lower price for use in industrial applications, e.g., as an agent in metal complexing and finishing. Glycine is not widely used in foods for its nutritional value, except in infusions. Instead, glycine's role in food chemistry is as a flavorant. It is mildly sweet, and it counters the aftertaste of saccharine . It also has preservative properties, perhaps owing to its complexation to metal ions. Metal glycinate complexes, e.g. copper(II) glycinate are used as supplements for animal feeds. As of 1971 ,

630-499: Is the only achiral proteinogenic amino acid . It can fit into hydrophilic or hydrophobic environments, due to its minimal side chain of only one hydrogen atom. Glycine was discovered in 1820 by French chemist Henri Braconnot when he hydrolyzed gelatin by boiling it with sulfuric acid . He originally called it "sugar of gelatin", but French chemist Jean-Baptiste Boussingault showed in 1838 that it contained nitrogen. In 1847 American scientist Eben Norton Horsford , then

672-469: Is then converted to pyruvate by serine dehydratase . In the third pathway of its degradation, glycine is converted to glyoxylate by D-amino acid oxidase . Glyoxylate is then oxidized by hepatic lactate dehydrogenase to oxalate in an NAD -dependent reaction. The half-life of glycine and its elimination from the body varies significantly based on dose. In one study, the half-life varied between 0.5 and 4.0 hours. The principal function of glycine

714-598: Is then metabolized by glycine N -acyltransferase into hippuric acid. In the US, glycine is typically sold in two grades: United States Pharmacopeia ("USP"), and technical grade. USP grade sales account for approximately 80 to 85 percent of the U.S. market for glycine. If purity greater than the USP standard is needed, for example for intravenous injections, a more expensive pharmaceutical grade glycine can be used. Technical grade glycine, which may or may not meet USP grade standards,

756-463: Is thought to be a hepatic detoxifier of a number endogenous and xenobiotic organic acids. Bile acids are normally conjugated to glycine in order to increase their solubility in water. The human body rapidly clears sodium benzoate by combining it with glycine to form hippuric acid which is then excreted. The metabolic pathway for this begins with the conversion of benzoate by butyrate-CoA ligase into an intermediate product, benzoyl-CoA , which

798-442: The ammonolysis of 2-bromopropanoic acid . Alanine is broken down by oxidative deamination , the inverse reaction of the reductive amination reaction described above, catalyzed by the same enzymes. The direction of the process is largely controlled by the relative concentration of the substrates and products of the reactions involved. Alanine is one of the twenty canonical α-amino acids used as building blocks (monomers) for

840-457: The citric acid cycle . L -Alanine is produced industrially by decarboxylation of L -aspartate by the action of aspartate 4-decarboxylase . Fermentation routes to L -alanine are complicated by alanine racemase . Racemic alanine can be prepared by the condensation of acetaldehyde with ammonium chloride in the presence of sodium cyanide by the Strecker reaction , or by

882-432: The codons starting with GG (GGU, GGC, GGA, GGG). Glycine is integral to the formation of alpha-helices in secondary protein structure due to the "flexibility" caused by such a small R group. Glycine is also an inhibitory neurotransmitter – interference with its release within the spinal cord (such as during a Clostridium tetani infection) can cause spastic paralysis due to uninhibited muscle contraction. It

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924-431: The urea cycle to form urea which is excreted through the kidneys. The glucose–alanine cycle enables pyruvate and glutamate to be removed from muscle and safely transported to the liver. Once there, pyruvate is used to regenerate glucose, after which the glucose returns to muscle to be metabolized for energy: this moves the energetic burden of gluconeogenesis to the liver instead of the muscle, and all available ATP in

966-791: The Republic of Venda Geological Curators' Group , a UK charity promoting geology Global Church of God , a Sabbatarian church based in England Government College Gujranwala , in Pakistan The Grilled Cheese Grill , an American restaurant chain Guardian Capital Group , a Canadian financial services company Gwaun-Cae-Gurwen , a village in Neath Port Talbot, Wales Knight Grand Cross of

1008-557: The Royal Guelphic Order , a Hanoverian order of chivalry Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title GCG . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=GCG&oldid=1054735409 " Category : Disambiguation pages Hidden categories: Short description

1050-400: The U.S. Food and Drug Administration "no longer regards glycine and its salts as generally recognized as safe for use in human food", and only permits food uses of glycine in certain conditions. Glycine has been researched for its potential to extend life . The proposed mechanisms of this effect are its ability to clear methionine from the body, and activating autophagy . Glycine

1092-511: The United States and Japan. About 15 thousand tonnes are produced annually in this way. Glycine is also co-generated as an impurity in the synthesis of EDTA , arising from reactions of the ammonia co-product. Its acid–base properties are most important. In aqueous solution, glycine is amphoteric : below pH = 2.4, it converts to the ammonium cation called glycinium. Above about pH 9.6, it converts to glycinate. Glycine functions as

1134-418: The amine becomes quaternized to give trimethylglycine , a natural product: Glycine condenses with itself to give peptides, beginning with the formation of glycylglycine : Pyrolysis of glycine or glycylglycine gives 2,5-diketopiperazine , the cyclic diamide. Glycine forms esters with alcohols . They are often isolated as their hydrochloride , such as glycine methyl ester hydrochloride . Otherwise,

1176-422: The bloodstream, and is transported to the liver. The alanine aminotransferase reaction takes place in reverse in the liver, where the regenerated pyruvate is used in gluconeogenesis , forming glucose which returns to the muscles through the circulation system. Glutamate in the liver enters mitochondria and is broken down by glutamate dehydrogenase into α-ketoglutarate and ammonium , which in turn participates in

1218-429: The cofactor pyridoxal phosphate : In E. coli , glycine is sensitive to antibiotics that target folate. In the liver of vertebrates , glycine synthesis is catalyzed by glycine synthase (also called glycine cleavage enzyme). This conversion is readily reversible : In addition to being synthesized from serine, glycine can also be derived from threonine , choline or hydroxyproline via inter-organ metabolism of

1260-441: The diet. Alanine is found in a wide variety of foods, but is particularly concentrated in meats. Alanine can be synthesized from pyruvate and branched chain amino acids such as valine , leucine , and isoleucine . Alanine is produced by reductive amination of pyruvate , a two-step process. In the first step, α-ketoglutarate , ammonia and NADH are converted by glutamate dehydrogenase to glutamate , NAD and water. In

1302-457: The free ester tends to convert to diketopiperazine . As a bifunctional molecule, glycine reacts with many reagents. These can be classified into N-centered and carboxylate-center reactions. Glycine is not essential to the human diet , as it is biosynthesized in the body from the amino acid serine , which is in turn derived from 3-phosphoglycerate . In most organisms, the enzyme serine hydroxymethyltransferase catalyses this transformation via

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1344-431: The free radical content can later be measured by electron paramagnetic resonance in order to find out how much radiation the alanine was exposed to. This is considered to be a biologically relevant measure of the amount of radiation damage that living tissue would suffer under the same radiation exposure. Radiotherapy treatment plans can be delivered in test mode to alanine pellets, which can then be measured to check that

1386-409: The intended pattern of radiation dose is correctly delivered by the treatment system. Glycine Glycine (symbol Gly or G ; / ˈ ɡ l aɪ s iː n / ) is an amino acid that has a single hydrogen atom as its side chain . It is the simplest stable amino acid ( carbamic acid is unstable). Glycine is one of the proteinogenic amino acids . It is encoded by all

1428-479: The key precursor to porphyrins , is biosynthesized from glycine and succinyl-CoA by the enzyme ALA synthase . Glycine provides the central C 2 N subunit of all purines . Glycine is an inhibitory neurotransmitter in the central nervous system , especially in the spinal cord , brainstem , and retina . When glycine receptors are activated, chloride enters the neuron via ionotropic receptors, causing an inhibitory postsynaptic potential (IPSP). Strychnine

1470-440: The liver and kidneys. Glycine is degraded via three pathways. The predominant pathway in animals and plants is the reverse of the glycine synthase pathway mentioned above. In this context, the enzyme system involved is usually called the glycine cleavage system : In the second pathway, glycine is degraded in two steps. The first step is the reverse of glycine biosynthesis from serine with serine hydroxymethyl transferase. Serine

1512-474: The muscle can be devoted to muscle contraction. It is a catabolic pathway, and relies upon protein breakdown in the muscle tissue. Whether and to what extent it occurs in non-mammals is unclear. Alterations in the alanine cycle that increase the levels of serum alanine aminotransferase (ALT) are linked to the development of type II diabetes. Alanine is useful in loss of function experiments with respect to phosphorylation . Some techniques involve creating

1554-463: The ribosome-mediated biosynthesis of proteins. Alanine is believed to be one of the earliest amino acids to be included in the genetic code standard repertoire. On the basis of this fact the "alanine world" hypothesis was proposed. This hypothesis explains the evolutionary choice of amino acids in the repertoire of the genetic code from a chemical point of view. In this model the selection of monomers (i.e. amino acids) for ribosomal protein synthesis

1596-522: The second step, the amino group of the newly formed glutamate is transferred to pyruvate by an aminotransferase enzyme, regenerating the α-ketoglutarate, and converting the pyruvate to alanine. The net result is that pyruvate and ammonia are converted to alanine, consuming one reducing equivalent . Because transamination reactions are readily reversible and pyruvate is present in all cells, alanine can be easily formed and thus has close links to metabolic pathways such as glycolysis , gluconeogenesis , and

1638-444: The secondary structure remains intact. The fact that alanine mimics the secondary structure preferences of the majority of the encoded amino acids is practically exploited in alanine scanning mutagenesis. In addition, classical X-ray crystallography often employs the polyalanine-backbone model to determine three-dimensional structures of proteins using molecular replacement —a model-based phasing method. In mammals, alanine plays

1680-426: The tissues of many crustaceans and molluscs as an osmolyte . Alanine was first synthesized in 1850 when Adolph Strecker combined acetaldehyde and ammonia with hydrogen cyanide . The amino acid was named Alanin in German, in reference to aldehyde , with the interfix -an- for ease of pronunciation, the German ending -in used in chemical compounds being analogous to English -ine . Alanine

1722-413: Was an amine of acetic acid . Although glycine can be isolated from hydrolyzed proteins , this route is not used for industrial production, as it can be manufactured more conveniently by chemical synthesis. The two main processes are amination of chloroacetic acid with ammonia , giving glycine and hydrochloric acid , and the Strecker amino acid synthesis , which is the main synthetic method in

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1764-532: Was confirmed in 2009, based on the analysis of samples that had been taken in 2004 by the NASA spacecraft Stardust from comet Wild 2 and subsequently returned to Earth. Glycine had previously been identified in the Murchison meteorite in 1970. The discovery of glycine in outer space bolstered the hypothesis of so-called soft-panspermia , which claims that the "building blocks" of life are widespread throughout

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