Xi:刺激性物质;
56-85-9Relevant articles and documents
A PROCESS FOR THE PREPARATION OF L-GLUTAMINE
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Page/Page column 13; 14; 15; 16, (2022/01/24)
The present invention relates to a process for the preparation of L-Glutamine of Formula (I). The present invention also relates to an improved process for the purification of L-Glutamine of Formula (I) having specific bulk density and Hausner ratio.
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.
A novel strategy for efficient chemoenzymatic synthesis of D-glutamine using recombinant Escherichia coli cells
Du, Qinglin,Zhang, Xiangyang,Pan, Xinru,Zhang, Hongjuan,Yang, Yu-Shun,Liu, Junzhong,Jiao, Qingcai
, (2020/06/17)
D-glutamine is a D type stereoisomer of glutamine which is involved in many metabolic processes. Seeking lower-cost and industrially scalable approaches for the synthesis of D-glutamine is very valuable both in academic career and potential applications. Herein, we developed a novel efficient chemoenzymatic strategy for producing D-glutamine. Initially, DL-glutamine was chemically prepared with cheap and accessible DL-glutamic acid as raw material. Subsequently, the L-glutamine among the racemic mixture was selectively hydrolyzed to L-glutamic acid by Escherichia coli whole-cell system which expressed L-aminopeptidase D-Ala-esterase/amidase (DmpA) from Ochrobactrum anthropi. The left D-glutamine was obtained by isoelectric point precipitation with 70% of the theoretical yield. Furthermore, we optimized enzymatic resolution conditions to determine the optimum parameters as pH 8, 30 °C, 0.1% (v/v) Triton X-100, and 1 mM Mn2+. These results suggested that our strategy might be potentially usable for the synthesis of D-glutamine in industrial productions.
Discovery of new A- and B-type laxaphycins with synergistic anticancer activity
Cai, Weijing,Matthew, Susan,Chen, Qi-Yin,Paul, Valerie J.,Luesch, Hendrik
, p. 2310 - 2319 (2018/04/02)
Two new cyclic lipopeptides termed laxaphycins B4 (1) and A2 (2) were discovered from a collection of the marine cyanobacterium Hormothamnion enteromorphoides, along with the known compound laxaphycin A. The planar structures were solved based on a combined interpretation of 1D and 2D NMR data and mass spectral data. The absolute configurations of the subunits were determined by chiral LC-MS analysis of the hydrolysates, advanced Marfey's analysis and 1D and 2D ROESY experiments. Consistent with similar findings on other laxaphycin A- and B-type peptides, laxaphycin B4 (1) showed antiproliferative effects against human colon cancer HCT116 cells with IC50 of 1.7 μM, while laxaphycins A and A2 (2) exhibited weak activities. The two major compounds isolated from the sample, laxaphycins A and B4, were shown to act synergistically to inhibit the growth of HCT116 colorectal cancer cells.
Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase
Taylor, Zane W.,Chamberlain, Alexandra R.,Raushel, Frank M.
, (2018/09/21)
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated (Enz-X-Pβ-Pγ) and phosphorylated (Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
Studies on the Biochemical Formation Pathway of the Amino Acid l -Theanine in Tea (Camellia sinensis) and Other Plants
Cheng, Sihua,Fu, Xiumin,Wang, Xiaoqin,Liao, Yinyin,Zeng, Lanting,Dong, Fang,Yang, Ziyin
, p. 7210 - 7216 (2017/08/30)
Tea (Camellia sinensis) is the most widely consumed beverage aside from water. The flavor of tea is conferred by certain metabolites, especially l-theanine, in C. sinensis. To determine why more l-theanine accumulates in C. sinensis than in other plants, we compare l-theanine contents between C. sinensis and other plant species (Camellia nitidissima, Camellia japonica, Zea mays, Arabidopsis thaliana, and Solanum lycopersicum) and use a stable isotope labeling approach to elucidate its biosynthetic route. We quantify relevant intermediates and metabolites by mass spectrometry. l-Glutamic acid, a precursor of l-theanine, is present in most plants, while ethylamine, another precursor of l-theanine, specifically accumulates in Camellia species, especially C. sinensis. Most plants contain the enzyme/gene catalyzing the conversion of ethylamine and l-glutamic acid to l-theanine. After supplementation with [2H5]ethylamine, all the plants produce [2H5]l-theanine, which suggests that ethylamine availability is the reason for the difference in l-theanine accumulation between C. sinensis and other plants.
Process for preparing hyperpolarized substrates and method for MRI
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Page/Page column 32, (2017/08/01)
The present invention generally relates to a process for the preparation of aqueous solutions of hyperpolarized molecules ready for use in in-vivo MR diagnostic imaging, the use thereof as MRI contrast agent in investigation methods for producing diagnostic MR images of a human or non-human animal body organ, region or tissue.
Tetrabutylammonium Fluoride as a Mild and Versatile Reagent for Cleaving Boroxazolidones to Their Corresponding Free α-Amino Acids
Poulie, Christian B. M.,Bunch, Lennart
supporting information, p. 1475 - 1478 (2017/04/01)
Protection of α-amino acids with 9-borabicyclo[3.3.1]nonane (9-BBN) to give their corresponding boroxazolidones is highly attractive, as it concurrently masks both the amino and the carboxylic acid functionalities. However, the harsh methods required for deprotection of these boroxazolidones have limited their use. Herein, we report that tetrabutylammonium fluoride serves as a mild and versatile reagent that can be used to cleave boroxazolidones to their corresponding free α-amino acids. The reaction conditions were explored, including the use of various nucleophilic fluoride sources, solvents, and reaction temperatures. Nucleophilic fluoride sources comprising an ammonium cation proved superior to other countercations. The scope of the reaction was extended to the cleavage of B,B-diphenyl- and B,B-diethyl boroxazolidone complexes. Furthermore, a wide range of α-amino acid side-chain functionalities were shown to be compatible, including acids, esters, amides, thiols, thioethers, alkynes, phenols, basic heterocycles, and important biorelevant molecules such as glutathione, (S)-adenosyl-l-homocysteine, and l-biocytin.
Chromatographic Resolution of α-Amino Acids by (R)-(3,3'-Halogen Substituted-1,1'-binaphthyl)-20-crown-6 Stationary Phase in HPLC
Wu, Peng,Wu, Yuping,Zhang, Junhui,Lu, Zhenyu,Zhang, Mei,Chen, Xuexian,Yuan, Liming
supporting information, p. 1037 - 1042 (2017/07/25)
Three new chiral stationary phases (CSPs) for high-performance liquid chromatography were prepared from R-(3,3'-halogen substituted-1,1'-binaphthyl)-20-crown-6 (halogen = Cl, Br and I). The experimental results showed that R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 (CSP-1) possesses more prominent enantioselectivity than the two other halogen-substituted crown ether derivatives. All twenty-one α-amino acids have different degrees of separation on R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6-based CSP-1 at room temperature. The enantioselectivity of CSP-1 is also better than those of some commercial R-(1,1'-binaphthyl)-20-crown-6 derivatives. Both the separation factors (α) and the resolution (Rs) are better than those of commercial crown ether-based CSPs [CROWNPAK CR(+) from Daicel] under the same conditions for asparagine, threonine, proline, arginine, serine, histidine and valine, which cannot be separated by commercial CR(+). This study proves the commercial usefulness of the R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 chiral stationary phase.
METHOD FOR SYNTHESIZING OPTICALLY ACTIVE a-AMINO ACID USING CHIRAL METAL COMPLEX COMPRISING AXIALLY CHIRAL N-(2-ACYLARYL)-2-[5,7-DIHYDRO-6H-DIBENZO[c,e]AZEPIN-6-YL] ACETAMIDE COMPOUND AND AMINO ACID
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Paragraph 0416-0417, (2016/05/10)
Objects of the present invention are to provide an industrially applicable method for producing an optically active α-amino acid in high yield and in a highly enantioselective manner, to provide a simple production method of an optically active α,α-disubstituted α-amino acid, and to provide an intermediate useful for the above production methods of an optically active α-amino acid and an optically active α,α-disubstituted α-amino acid. The present invention provides a production method of an optically active α-amino acid or a salt thereof, the production method comprising introducing a substituent into the α carbon in the α-amino acid moiety of a metal complex represented by the following Formula (1): by an alkylation reaction, an aldol reaction, the Michael reaction, or the Mannich reaction, and releasing an optically pure α-amino acid enantiomer or a salt thereof by acid decomposition of the metal complex.
