52-90-4 Usage
description
L-Cysteine is one of the 20 natural amino acids and, besides methionine,the only one which contains sulfur. It is a thiol-containing non-essential amino acid that is oxidized to form Cystine. It is a non-essential sulfur-containing amino acid in humans, related to cystine, Cysteine is important for protein synthesis, detoxification, and diverse metabolic functions. Found in beta-keratin, the main protein in nails, skin, and hair, Cysteine is important in collagen production, as well as skin elasticity and texture. Also required in the manufacture of amino acid taurine, Cysteine is a component of the antioxidant glutathione, and plays a role in the metabolism of essential biochemicals such as coenzyme A, heparin, and biotin.
L-cysteine hydrochloride is used in the baking industry as dough conditioner. Specially, it breaks the disulfide bonds of gluten, which lowers the viscosity of the dough. It is then easier to work with and increases the elasticity of the dough, helping it to rise during baking.
L-cysteine is available through many dietary sources, primarily animal protein. Eggs and dairy products also contain significant levels of l-cysteine. Vegetable sources of l-cysteine include broccoli, Brussels sprouts, garlic, granola, sprouted lentils, oats, onions and peppers. The commercial extraction of l-cysteine typically uses human hair, due to its high concentration of this amino acid. Other commercial sources include hog hair and poultry feathers. L-cysteine may also be synthesized in a process that involves fermentation by a variety of E. coli.
Chemical properties
L-cysteine (chemical name, 2-amino-3-mercaptopropionic acid or mercapto alanine) is a mercapto-containing aliphatic neutral amino acid. It is colorless crystal with isoelectric point of 5.07, PK1 = 1.71, pK2 = 8.33, and pK3 = 10.78. It is Soluble in water, ethanol, acetic acid and ammonia, while not soluble in benzene, carbon tetrachloride, ethyl acetate, carbon disulfide, ether and acetone. L-cysteine is an essential component of the protein and can be synthesized from serine or methionine in animals. L-cysteine comes to decompose while heated to 240 ° C, and can be quickly oxidized by air to form cystine in neutral or slightly alkaline solution. The acid solution of L-cysteine can be stored for several days, and stored better under the protection of nitrogen. The aqueous solution of levorotatory L-cysteine changes into dark blue after adding ferric chloride. It can be produced by the degradation of cystine, and also can be obtained by the hydrochloric acid hydrolysis, copper oxide treatment and then hydrogen sulfide decomposition of human hair and other silkworm. L-cysteine can be used for anti-radiation and the treatment of radiation sickness, as well as for hepatitis, liver poisoning, radiopharmaceutical poisoning, acrylonitrile and antimony poisoning and allergic diseases in medicine. It can also be applied for the biochemical and nutritional research. Pyruvate and mercaptoethanamine are its general catabolites. It is involved in the synthesis of glutathione, taurine and so on. The disulfide bridge in the polypeptide chain is also formed by dehydrogenation and condensation of two molecules of cysteine.
Amino acids
L-cysteine, also known as cysteine, is a non-essential amino acid of the human body. Amino acids are protein components and protein is the material basis of life. Ranging from human to microorganism, all consist of protein. Protein is composed of peptides, and peptide chain is composed of amino acids. Different proteins are composed of peptide chains in different order and length. Genes related to heredity are in fact amino acid chains in different orders.
L-cysteine is closely related to cysteine, and two molecules of cysteine can form a cysteine. Cysteine is relatively unstable and easy to become cysteine. Cystine can also re-generate cysteine. These two both are sulfur-containing amino acids, which affect the formation of skin and can be used for detoxification.
L-cysteine is present in keratin, which is the major protein that makes up nails, toenails, skin and hair. L-cysteine can help the production of collagen, and can maintain the skin's elasticity and texture. It is also related to the protein of digestive enzymes, and cysteine can supply –SH group to many important enzymes, such as succinate dehydrogenase and lactate dehydrogenase.
L-cysteine is mainly used in the field of cosmetics, medicine and food. In cosmetics, it can be used for the preparation of perm essence, sunscreen, hair-restoring perfume and other nourishing hair essence. In the field of medicine, it is mainly used for the preparation of methyl cysteine, ethyl cysteine, acetyl cysteine, cysteine methyl ester, cysteine ethyl ester as well as comprehensive amino acid preparations and other drugs. Cysteine can be used as protective agent for radiation damage. In food, L-cysteine can be used as bread fermentation aid (ripening agent), stabilizer of milk powder and fruit juice antioxidants and nutrition of pet food and so on.
The above information is edited by andy of lookchem.
health benefits
L-cysteine is an important precursor for antioxidants such as glutathione – a product metabolized in the liver. Glutathione is essential for the breakdown of toxins in the body, such as alcohol. L-cysteine is also the precursor for other important antioxidants that help ward off cancer by decreasing the incidence of cell mutation.
Cancer is caused by the replication of genetic mistakes (mutations) that go unnoticed by the cell’s recognition system. In healthy cells, mutations are caught and denatured before replication continues.
If mutations are not caught, then the on/off mechanisms that monitor cell formation may be disrupted allowing uncontrolled proliferation of cells into tumors. A healthy cell rich in amino acids such as L-cysteine, has a better chance of sensing and discarding such mutations.
L-cysteine benefits can also include improved heart and circulatory system health. Inflammation plays a key role in heart health. The inflammation response causes a cascade of events to bring fluids, proteins and cells to damaged tissues.
Some of these substances carried in an inflammatory response are sticky and can get stuck on the walls of arteries. The presence of L-cysteine has been found to directly regulate this adhesion of sticky substances to the walls of arteries and therefore has a positive effect on the health of our hearts.
figure 1: L-Cysteine 500mg, 100 Tablets
Uses
Different sources of media describe the Uses of 52-90-4 differently. You can refer to the following data:
1. L-cysteine can be used as bread improver, nutritional supplements, antioxidants and color fixative. It can also be applied for curing acrylonitrile and aromatic acid poisoning, preventing radiation damage and treating bronchitis and phlegm. L-cysteine can absorb alcohol and convert it into acetaldehyde to alleviate a hangover.
L-cysteine can be used for the treatment of eczema, urticaria, freckles and other skin diseases. And its series products are widely used in medicine, food and cosmetics industry
L-cysteine can be used for biochemical research and as the antidote for hepatitis, liver poisoning, radiopharmaceutical poisoning, antimony poisoning, etc.
L-cysteine is mainly used for medicine, cosmetics, biochemical research and so on. It can be used in the bread material to accelerate the formation of gluten and to promote fermenting and depanning, as well as to prevent aging. It can be used in natural fruit juices to prevent oxidation of vitamin C and to prevent fruit juice from becoming brown. The product has detoxification effect and can be used for curing acrylonitrile poisoning and aromatic acidosis. This product also has the role of preventing the human body from radiation damage. It can be used as bronchitis drugs, especially as phlegm drugs (mostly in the form of acetyl L-cysteine methyl ester salt). In cosmetics, it is mainly used as cosmetic water, perm solution, anti-sun cream and other skin care.
L-cysteine can be used as the receptor agonists of NMDA glutamate.
2. L-Cysteine is a non-essential amino acid that can be synthesized by the human body under normal physiological conditions if a sufficient quantity of methionine is available. L-Cysteine is commonly used as a precursor in the food and pharmaceutical industries. L-Cysteine is used as a processing aid for baking, as an additive in cigarettes, as well as in the preparation of meat flavours. It is used in foods to prevent oxygen from destroying vitamin c and is used in doughs to reduce mixing time.
Cysteine Metabolism
Cysteine is a sulfur-containing amino acid that constitutes protein. It has an ionized mercapto side chain and is hydrophobic. However, it is unstable in neutral pH or alkaline pH in the air, and its aqueous solution can automatically convert into cysteine .
Although cystine does not belong to the list of amino acids composing protein, but in the process of protein conformation, it can generate by oxidizing the SH group of two close cysteine, so many protein molecules in the body contain cystine. The formation of cystine disulfide bond makes the protein conformation more stable. Of course, if the cystine is reduced, it can also produce two molecules of cysteine.
The importance of cysteine as a protein component is to give the active protein a free SH group, for example, the active centers of some proteases (papain, bromelain) and glyceraldehyde phosphate dehydrogenase all regard SH group as their function base.
The metabolic pathway of cysteine carbon skeleton is mainly to form pyruvate and generate oxaloacetate through carboxylation for gluconeogenesis, so cysteine belongs to the glucogenic amino acid, or to change into acetyl-CoA and come into the tricarboxylic acid cycle for complete oxidization. There may be three ways for cysteine transforming into pyruvate.
Non-protein nitrogenous compounds synthesized or part-synthesized by cysteine include taurine, peroxydihydroxyethylamine, coenzyme A and glutathione.
Production methods
1. Tin granule reduction method. Dissolve cystine in dilute hydrochloric acid and filtrate. Add tin granules into the filtrate and heat for reflux of 2h. Dilute the reducing solution with water and remove the residual tin particles. Saturate the diluted solution with hydrogen sulfide and filtrate. Wash the residue with a small amount of water and combine the washing liquor with filtrate. Then concentrate the mixture under reduced pressure, cool for crystallization, filtrate and dry to obtain L-cysteine hydrochloride.
2. Electrolysis reduction method. Add distilled water, hydrochloric acid, cystine into the electrolytic tank and dissolve under stirring. Maintain at 50℃ until the electrolysis to the end. Add hydrogen sulphide to pass through the resultant electrolytic solution for several hours and filtrate. Decolorize the filtrate with activated carbon, filtrate and concentrate under reduced pressure. Cool for crystallization, filtrate and then dry to give L-cysteine hydrochloride.
3. Use L-cysteine hydrochloride as raw materials. Neutralize L-cysteine hydrochloride with alkali and obtain L-cysteine after further purification.
4. Heat the hair (or animal hair, feathers) with hydrochloric acid for 6~8h and then hydrolyze. Remove the hydrochloric acid by vacuum distillation. Add activated carbon for decolorization, Filtrate and neutralize with ammonia to obtain L-cystine crude crystals. And then dissolve with ammonia solution for recrystallization. Next dissolve with hydrochloric acid again and perform electrolytic reduction. The resultant electrolytic solution is concentrated, cooled for crystallization and dried to obtain the product.
synthesis
Cysteine can be prepared in three ways:
1, extraction method: process the hair (or feather powder) into cystine, dissolve in hydrochloric acid, and then obtain L-cysteine hydrochloride by electrolysis or the reduction of tin and hydrochloric acid
Methods for Extracting Cysteine from Hair
2, synthesis method: the current industrial applications include β-chloroalanine method, α-bromo-methyl acrylate and Degussa method.
Use α-chloroacrylic acid methyl ester and thiourea as raw materials to firstly synthesize DL-2-aminothiazoline-4-carboxylic acid and then carry out asymmetric hydrolysis under the action of Pseudomonas aeruginosa enzyme to obtain the product.
Use methyl α-bromo-acrylic acid as raw materials to react with methyl thioacetamide and form 2-methyl-thiazoline-4-carboxylic acid methyl ester. The product can be obtained after?? further hydrolysis.
α-methyl bromoacrylate method: use chloroacetaldehyde as raw materials to react with sodium bisulfate and form α-hydroxy-β-chloro ethanol sodium sulfonate [2]. [2] and ammonium hydroxide react to form α-amino-β-chlorosulfonate [3]. [3] and sodium hydride react to obtain α-amino-β-chloropropionitrile[4]. After the hydrolysis of [4], β-chloroalanine [5] is generated. Then [5] and ammonium thiosulfate react and hydrolyze to form DL-cysteine precipitation. And L-cysteine can be finally obtained after further desalination.
3, enzymatic method (Ajinomoto method): use α-chloro acrylic acid methyl ester and thiourea as raw materials to firstly synthesize DL-2-aminothiazoline-4-carboxylic acid (DL-ATC). L-cysteine is produced by the asymmetric hydrolysis of DL-ATC in the presence of the three enzymes of thermophilic thiazole pseudomonas bacteria.
physiological effects
Cysteine can help the detoxification of the body. It is the best free radical scavenger combined with selenium and vitamin E. Cysteine is also the precursor of glutathione, which is capable of binding with poisonous substances for detoxication in the liver. It can protect the liver and brain from the damage of cigarettes, alcohol and drugs.
Since cysteine is more soluble than cystine, it is easier for cysteine to be used by the body to treat various diseases. Vitamin B6 is required for in vivo cysteine synthesis. Cysteine can not be synthesized in the presence of chronic conditions, so people with chronic diseases need a higher dose of cysteine, for example, 3 times a day for 1 month.
The patients with rheumatoid arthritis, vascular sclerosis or cancer need to supplement cysteine. Cysteine can also assists people to accelerate recovery after surgery and burns. It can form complexes with heavy metals, and enhance iron absorption. These two amino acids can also accelerate the use of fat and formation of muscle. Cysteine can clears mucus in the respiratory tract, so it can treat bronchitis, emphysema and tuberculosis.
Cysteine (or acetyl-linked acetylcysteine) can be used to prevent the side effects in cancer chemotherapy or radiation therapy. It can also increase the level of glutathione in lung, kidney, liver and bone marrow, so it has anti-aging effects, for example, it can reduce the incidence of age spots.
Cysteine can inactivates insulin. Therefore, patients with diabetes can not take cysteine. Genetic cystinuria can result in cystine stones, so people with genetic cystinuria can not take these two amino acids.
Description
Cysteine (abbreviated as Cys or C) is an α-amino acid with the chemical formula HO2CCH(NH2)CH2SH. It is a semi - essential amino acid, which means that it can be biosynthesized in humans. The thiol side chain in cysteine often participates in enzymatic reactions, serving as a nucleophile. The thiol is susceptible to oxidization to give the disulfide derivative cystine, which serves an important structural role in many proteins. When used as a food additive, it has the E number E920.
Chemical Properties
A sulfur-containing amino acid, metabolically related to methionine. Methionine is the source of sulfur atom in the
synthesis of cysteine in the body. Chemically, L-cysteine is L-2-amino-mercaptopropionic acid. Cysteine has a sulfureous aroma. It
is a nutrient and is used in dietary supplements.
Occurrence
Dietary sources Although classified as a non-essential amino acid, in rare cases, cysteine may be essential for infants, the elderly, and individuals with certain metabolic disease or who suffer from malabsorption syndromes. Cysteine can usually be synthesized by the human body under normal physiological conditions if a sufficient quantity of methionine is available. Cysteine is catabolized in the gastrointestinal tract and blood plasma. In contrast, cystine travels safely through the GI tract and blood plasma and is promptly reduced to the two cysteine molecules upon cell entry. Industrial sources The majority of L - cysteine is obtained industrially by hydrolysis of poultry feathers or human hair. Synthetically produced L-cysteine, compliant with Jewish Kosher and Muslim Halal rules, is also available, albeit at a higher price. The synthetic route involves fermentation utilizing a mutant of E. coli. Biosynthesis In animals, biosynthesis begins with the amino acid serine. The sulfur is derived from methionine, which is converted to homocysteine through the intermediate S- adenosylmethionine. Cystathionine betasynthase then combines homocysteine and serine to form the asymmetrical thioether cystathionine. The enzyme cystathionine gamma-lyase converts the cystathionine into cysteine and alphaketobutyrate.
Definition
ChEBI: L-cysteine is an optically active form of cysteine having L-configuration. It has a role as a flour treatment agent, a human metabolite and an EC 4.3.1.3 (histidine ammonia-lyase) inhibitor. It is a serine family amino acid, a proteinogenic amino acid, a cysteine and a L-alpha-amino acid. It is a conjugate base of a L-cysteinium. It is a conjugate acid of a L-cysteinate(1-). It is an enantiomer of a D-cysteine. It is a tautomer of a L-cysteine zwitterion.
Application
Cysteine, mainly the L-enantiomer, is a precursor in the food, pharmaceutical, and personal care industries. One of the largest applications is the production of flavors. For example, the reaction of cysteine with sugars in a Maillard reaction yields meat flavors. Lcysteine is also used as a processing aid for baking. In the field of personal care, cysteine is used for permanent wave applications predominantly in Asia. Again the cysteine is used for breaking up the disulfide bonds in the hair's keratin. Cysteine is a very popular target for site-directed labeling experiments to investigate biomolecular structure and dynamics. Maleimides will selectively attach to cysteine using a covalent Michael addition. Site- directed spin labeling for EPR or paramagnetic relaxation enhanced NMR also uses cysteine extensively.cysteine is an essential amino acid obtained by fermentation. Cysteine is a component of the skin’s natural moisturizing factor and can help normalize oil gland secretion because of its sulfur content. It is also said to promote wound healing. In addition, studies indicate that cysteine helps increase levels of glutathione (an anti-oxidant) in the body. It is considered beneficial in treating oily skin.
Preparation
L-Cysteine used to be produced almost exclusively by hydrolysis of hair or other keratins. The amino acid isolated was l-cystine, which was reduced electrolytically to l-cysteine. L-Cysteine has also been prepared from beta-chloro-d,l-alanine and sodium sulfide with cysteine desulfhydrase, an enzyme obtained from, e.g., Citrobacterium freundii. Today, however, the main processes for cysteine production are biological. A direct fermentation process has been developed for the manufacture of l-cystine, using a modified Escherichia coli bacterium. The technology has been extended to prepare other modified l-cysteine analogues. An enzymatic process for l-cysteine has been successfully developed using microorganisms capable to hydrolyze 2-amino-delta2-thiazoline 4-carboxylic acid (ATC) which is readily available from methyl alpha-chloroacrylate and thiourea. A mutant of Pseudomonas thiazolinophilum converts d,l-ATC to l-cysteine in 95% molar yield at product concentrations higher than 30 g/L.
Biological Functions
The cysteine thiol group is nucleophilic and easily oxidized. The reactivity is enhanced when the thiol is ionized, and cysteine residues in proteins have pKa values close to neutrality, so are often in their reactive thiolate form in the cell. Because of its high reactivity, the thiol group of cysteine has numerous biological functions. Precursor to the antioxidant glutathione Due to the ability of thiols to undergo redox reactions, cysteine has antioxidant properties. Cysteine's antioxidant properties are typically expressed in the tripeptide glutathione, which occurs in humans as well as other organisms. Precursor to iron-sulfur clusters Cysteine is an important source of sulfide in human metabolism. The sulfide in iron-sulfur clusters and in nitrogenase is extracted from cysteine, which is converted to alanine in the process. Metal ion binding Beyond the iron - sulfur proteins, many other metal cofactors in enzymes are bound to the thiolate substituent of cysteinyl residues. Examples include zinc in zinc fingers and alcohol dehydrogenase, copper in the blue copper proteins, iron in cytochrome P450, and nickel in the [NiFe]-hydrogenases . The thiol group also has a high affinity for heavy metals, so that proteins containing cysteine, such as metallothionein, will bind metals such as mercury, lead, and cadmium tightly. Roles in protein structure In the translation of messenger RNA molecules to produce polypeptides, cysteine is coded for by the UGU and UGC codons. Cysteine has traditionally been considered to be a hydrophilic amino acid, based largely on the chemical parallel between its thiol group and the hydroxyl groups in the side-chains of other polar amino acids. However, the cysteine side chain has been shown to stabilize hydrophobic interactions in micelles to a greater degree than the side chain in the non-polar amino acid glycine, and the polar amino acid serine .
Synthesis Reference(s)
Chemical and Pharmaceutical Bulletin, 34, p. 869, 1986 DOI: 10.1248/cpb.34.869
General Description
L-cysteine is a sulfur-containing non-essential amino acid. Its ability to reduce colitis symptoms is being assessed for potential use in treating inflammatory bowel disease (IBD).
Biochem/physiol Actions
NMDA glutamatergic receptor agonist.
Side effects
Cysteine has been proposed as a preventative or antidote for some of the negative effects of alcohol, including liver damage and hangover. It counteracts the poisonous effects of acetaldehyde, which is the major by - product of alcohol metabolism and is responsible for most of the negative aftereffects and long - term damage associated with alcohol use (but not the immediate effects of drunkenness). Cysteine supports the next step in metabolism, which turns acetaldehyde into the relatively harmless acetic acid. In a rat study, test animals received an LD50 dose of acetaldehyde. Those that received cysteine had an 80 % survival rate; when both cysteine and thiamine were administered, all animals survived . There is not yet direct evidence for or against its effectiveness in humans who consume alcohol at normal levels. N-Acetylcysteine N - Acetyl - L - cysteine (NAC) is a derivative of cysteine wherein an acetyl group is attached to the nitrogen atom. This compound is sold as a dietary supplement and used as an antidote in cases of acetaminophen overdose, and obsessive compulsive disorders such as trichotillomania.
Safety Profile
Moderately toxic by
ingestion, intraperitoneal, and subcutaneous
routes. Experimental reproductive effects.
Human mutation data reported. When heated to decomposition fumes of SO and NO.
Purification Methods
Purify it by recrystallisation from H2O (free from metal ions) and dry it in a vacuum. It is soluble in H2O, EtOH, Me2CO, EtOAc, AcOH, *C6H6 and CS2. Acidic solutions can be stored under N2 for a few days without deterioration. [For synthesis and spectra see Greenstein & Winitz Chemistry of the Amino Acids (J. Wiley) Vol 3 p1879 1961, Beilstein 4 III 1618, 4 IV 3144.]
Sheep
Cysteine is required by sheep in order to produce wool: It is an essential amino acid that must be taken in as food from grass. As a consequence, during drought conditions, sheep stop producing wool; however, transgenic sheep that can make their own cysteine have been developed.
Check Digit Verification of cas no
The CAS Registry Mumber 52-90-4 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 5 and 2 respectively; the second part has 2 digits, 9 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 52-90:
(4*5)+(3*2)+(2*9)+(1*0)=44
44 % 10 = 4
So 52-90-4 is a valid CAS Registry Number.
InChI:InChI=1/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)/t2-/m0/s1
52-90-4Relevant articles and documents
A novel and environmentally friendly colorimetric method for detection of cystine in human urine using unmodified gold nanoparticles
Lu, Li-Qiang,Gao, Qian,Song, Chi,Tian, Xi-Ke,Xu, An-Wu
, p. 27297 - 27300 (2014)
Cystine was reduced by ascorbic acid to cysteine, which induced the aggregation of unmodified gold nanoparticles. The accompanied color change was distinguishable and perceivable by the naked eye. This facile assay method was successfully applied to the detection of cystine in human urine.
Biogenesis of Hydrogen Sulfide and Thioethers by Cystathionine Beta-Synthase
Majtan, Tomas,Krijt, Jakub,Sokolová, Jitka,K?í?ková, Michaela,Ralat, Maria A.,Kent, Jana,Gregory, Jesse F.,Ko?ich, Viktor,Kraus, Jan P.
, p. 311 - 323 (2018)
Aims: The transsulfuration pathway enzymes cystathionine beta-synthase (CBS) and cystathionine gamma-lyase are thought to be the major source of hydrogen sulfide (H2S). In this study, we assessed the role of CBS in H2S biogenesis. Results: We show that despite discouraging enzyme kinetics of alternative H2S-producing reactions utilizing cysteine compared with the canonical condensation of serine and homocysteine, our simulations of substrate competitions at biologically relevant conditions suggest that cysteine is able to partially compete with serine on CBS, thus leading to generation of appreciable amounts of H2S. The leading H2S-producing reaction is condensation of cysteine with homocysteine, while cysteine desulfuration plays a dominant role when cysteine is more abundant than serine and homocysteine is limited. We found that the serine-to-cysteine ratio is the main determinant of CBS H2S productivity. Abundance of cysteine over serine, for example, in plasma, allowed for up to 43% of CBS activity being responsible for H2S production, while excess of serine typical for intracellular levels effectively limited such activity to less than 1.5%. CBS also produced lanthionine from serine and cysteine and a third of lanthionine coming from condensation of two cysteines contributed to the H2S pool. Innovation: Our study characterizes the H2S-producing potential of CBS under biologically relevant conditions and highlights the serine-to-cysteine ratio as the main determinant of H2S production by CBS in vivo. Conclusion: Our data clarify the function of CBS in H2S biogenesis and the role of thioethers as surrogate H2S markers.
Developing potent backbone cyclic peptides bearing the shared epitope sequence as rheumatoid arthritis drug-leads
Naveh, Shirly,Tal-Gan, Yftah,Ling, Song,Hoffman, Amnon,Holoshitz, Joseph,Gilon, Chaim
, p. 493 - 496 (2012)
Rheumatoid arthritis (RA) is a common human leukocyte antigen-associated disease. Most RA patients have a five-residue sequence motif called the shared epitope (SE) in the DRβ-chain of the HLA-DRB1 protein. The SE was found to activate nitric oxide (NO) production, suggesting a possible mechanism for RA development. The native conformation of the SE is presumed to be an α-helix, thus using cyclic peptides to stabilize this conformation may produce a potent SE mimetic which will have drug-like properties. We present the development of a backbone cyclic SE mimetic that activates NO production in the low nM range. Circular dichroism analysis revealed a conformational change from for the parent linear peptides to the cyclic analogs. The most active cyclic analog is completely stable towards trypsin/chymotrypsin degradation while the linear 15-mer analogs completely degraded within 30 min. The outcome of this study is a potent cyclic peptide with drug-like properties that can be used as a template for drug development.
Racemization of Optically Active Cysteine via Formation of 2,2-Dimethyl-4-thiazolidinecarboxylic Acid
Shiraiwa, Tadashi,Kataoka, Kazuo,Sakata, Shinji,Kurokawa, Hidemoto
, p. 4158 - 4160 (1988)
Optically active cysteine (Cys) was racemized via formation of (RS)-2,2-dimethyl-4-thiazolidinecarboxylic acid ((RS)-DMT) by refluxing in the presence of acetone in 10-fold molar amount in acetic acid.The formed (RS)-DMT was hydrolyzed by adding water to the reaction mixture to give (RS)-Cys in 95-97percent yield.
Facile dimethylarsenic exchange and pyramidal inversion in its cysteine and glutathione adducts
Bohle, D. Scott,Gu, Yuxuan
, p. 2578 - 2581 (2013)
Rapid thiolate exchange of dimethylarsonium, Me2As+, is observed between two different thiolate species in solution. NMR is used to characterize the equilibrium constants for interthiol transfer as well the rapid intra molecular conf
Thermostability and reactivity in organic solvent of O-phospho-L-serine sulfhydrylase from hyperthermophilic archaeon Aeropyrum pernix K1
Nakamura, Takashi,Asai, Shinji,Nakata, Kaori,Kunimoto, Kohei,Oguri, Masateru,Ishikawa, Kazuhiko
, p. 1280 - 1286 (2015)
O-phospho-L-serine sulfhydrylase (OPSS) from archaeon Aeropyrum pernix K1 is able to synthesize L-cysteine even at 80 °C. In this article, we compared thermal stability and reactivity in organic solvent of OPSS with those of O-acetyl-L-serine sulfhydrylase B (OASS-B) from Escherichia coli. As a result, the thermostability of OPSS was much higher than that of OASS-B. Moreover, the activity of OPSS increased in the reaction mixture containing the organic solvent, such as N, N'-dimethyl formamide and 1,4-dioxane, whereas that of OASS-B gradually decreased as the content of organic solvent increased. From the crystal structural analysis, the intramolecular electrostatic interactions of N-terminal domain in OPSS seemed to be correlated with the tolerance of OPSS to high temperature and organic solvent. These results indicate that OPSS is more superior to OASS-B for the industrial production of L-cysteine and unnatural amino acids that are useful pharmaceuticals in the presence of organic solvent.
The structural and mutational analyses of O-ureido-L-serine synthase necessary for D-cycloserine biosynthesis
Uda, Narutoshi,Matoba, Yasuyuki,Oda, Kosuke,Kumagai, Takanori,Sugiyama, Masanori
, p. 3929 - 3944 (2015)
We have recently been successful in cloning a gene cluster necessary for the biosynthesis of d-cycloserine (d-CS) from d-CS-producing Streptomyces lavendulae ATCC11924. Although dcsD, one of the ORFs located on the gene cluster, encodes a protein homologous to O-acetylserine sulfhydrylase that synthesizes l-cysteine using O-acetyl-l-serine together with sulfide, it functions to form O-ureido-l-serine as a d-CS biosynthetic intermediate, using O-acetyl-l-serine together with hydroxyurea (HU). In the present study, using crystallographic and mutational studies, three amino acid residues in DcsD that are important for the substrate preference toward HU were determined. We showed that two of the three residues are important for the binding of HU into the substrate-binding pocket. The other residue contributes to the formation of a loose hydrogen-bond network during the catalytic reaction. Information regarding the amino acid residues will be very useful in the design of a new catalyst for synthesizing the β-substituted-L-alanine derivatives.
Direct monitoring of biocatalytic deacetylation of amino acid substrates by1H NMR reveals fine details of substrate specificity
De Cesare, Silvia,McKenna, Catherine A.,Mulholland, Nicholas,Murray, Lorna,Bella, Juraj,Campopiano, Dominic J.
supporting information, p. 4904 - 4909 (2021/06/16)
Amino acids are key synthetic building blocks that can be prepared in an enantiopure form by biocatalytic methods. We show that thel-selective ornithine deacetylase ArgE catalyses hydrolysis of a wide-range ofN-acyl-amino acid substrates. This activity was revealed by1H NMR spectroscopy that monitored the appearance of the well resolved signal of the acetate product. Furthermore, the assay was used to probe the subtle structural selectivity of the biocatalyst using a substrate that could adopt different rotameric conformations.
Synthesis method of DL-cysteine
-
Paragraph 0020-0022, (2021/02/13)
The invention discloses a synthetic method of DLcysteine. The method comprises the following steps: by using acrylonitrile as a raw material, chlorinating to generate 2, 3dichloropropionitrile, hydrolyzing to generate corresponding acid, reacting the acid with thiourea to cyclize to generate 2-aminothiazoline-4-carboxylic acid, adding alkali sulfide to generate 2-mercaptothiazoline-4-carboxylic acid, and hydrolyzing to generate cysteine. The synthesis method provided by the invention has the advantages of short synthesis steps, mild preparation conditions, sufficient and cheap raw material sources and higher product yield.
Dynamic Kinetic Resolution for Asymmetric Synthesis of L-Noncanonical Amino Acids from D-Ser Using Tryptophan Synthase and Alanine Racemase
Yu, Jinhai,Li, Jing,Gao, Xia,Zeng, Shuiyun,Zhang, Hongjuan,Liu, Junzhong,Jiao, Qingcai
, p. 6618 - 6625 (2019/11/03)
L-Ser is often used to synthesize some significant l-noncanonical α-amino acids(l-ncAAs), which are the prevalent intermediates and precursors for functional synthetic compounds. In this study, threonine aldolase from Escherichia coli k-12 MG1655 has been used to synthesize l-Ser. In contrast to the maximum catalytic capacity (20 g/L) for l-threonine aldolase(LTA), d-Ser was synthesized with high yield (240 g/L) from cheap Gly and paraformaldehyde using d-threonine aldolase (DTA) from Arthrobacter sp ATCC. In order to fully utilize d-Ser and expand the resource of l-Ser, a dynamic kinetic resolution system was constructed to convert d/dl-Ser to l-Ser through combining alanine racemase (Alr) from Bacillus subtilis with l-tryptophan synthase (TrpS) from Escherichia coli k-12 MG1655, and l-ncAAs including l-Trp and l-Cys derivatives were synthesized with excellent enantioselectivity and in high yields. The results indicated l-ncAAs could be efficiently synthesized from d-Ser using this original and green dynamic kinetic resolution system, and the reliable l-Ser resource has been established from simple and achiral substrates.
