1113-60-6Relevant articles and documents
One-Pot Preparation of d-Amino Acids Through Biocatalytic Deracemization Using Alanine Dehydrogenase and Ω-Transaminase
Han, Sang-Woo,Shin, Jong-Shik
, p. 3678 - 3684 (2018)
d-Amino acids are pharmaceutically important building blocks, leading to a great deal of research efforts to develop cost-effective synthetic methods. Preparation of d-amino acids by deracemization has been conceptually attractive owing to facile synthesis of racemic amino acids by Strecker synthesis. Here, we demonstrated biocatalytic deracemization of aliphatic amino acids into d-enantiomers by running cascade reactions; (1) stereoinversion of l-amino acid to a d-form by amino acid dehydrogenase and ω-transaminase and (2) regeneration of NAD+ by NADH oxidase. Under the cascade reaction conditions containing 100?mM isopropylamine and 1?mM NAD+, complete deracemization of 100?mM dl-alanine was achieved after 24?h with 95% reaction yield of d-alanine (> 99% eeD, 52% isolation yield). Graphical Abstract: [Figure not available: see fulltext.].
MECHANISTIC STUDY OF THE ALDOL CONDENSATION OCCURING IN THE ALKALINE SOLUTION OF 3-HYDROXY 2-OXO PROPRANOATE (Β HYDROXYPYRUVATE)
Fleury, Daniele,Fleury, M. B.,Platzer, Nicole
, p. 493 - 502 (1981)
With 3-bromo-2-oxopropanoate (β bromopyruvate) and its ethyl ester, the ionisation of the gemdiol of the hydrated form BrCH2-C(OH)2-COOR 1 initiates the elimination of the bromide anion yielding 3-hydroxy-2-oxopropanoate 2 (β-hydroxypyruvate).The mechanism of the reaction was investigated essentially by polarography in aqueous solution.In neutral ( and acid) media, the polarographic behaviour of 2 resembled that of other α-ketoacids: reduction at the mercury electrode yielded glycerate.In alkaline media, there was evidence of the carbanion enolate .3'.The overall rate constant was determined according to a kinetic law of the type: : found k = 1.56 min-1 in NaOH 0.5N at 25 deg.In the pH range 10.5 to 11.5, 3' existed in minor amounts and initiated a slow aldol codensation with the tautomer 3-oxo-2-hydroxypropanoate 4 (tartrone semialdehyde) according to a kinetic low of the type found at 25 deg., at pH 11.0.The aldol product was isolated as a sodium salt and its structure established by 13CNMR.
One-Pot Cascade Synthesis of (3S)-Hydroxyketones Catalyzed by Transketolase via Hydroxypyruvate Generated in Situ from d-Serine by d-Amino Acid Oxidase
L'enfant, Mélanie,Bruna, Felipe,Lorillière, Marion,Ocal, Nazim,Fessner, Wolf-Dieter,Pollegioni, Loredano,Charmantray, Franck,Hecquet, Laurence
, p. 2550 - 2558 (2019)
We described an efficient in situ generation of hydroxypyruvate from d-serine catalyzed by a d-amino acid oxidase from Rhodotorula gracilis. This strategy revealed an interesting alternative to the conventional chemical synthesis of hydroxypyruvate starting from toxic bromopyruvate or to the enzymatic transamination from l-serine requiring an additional substrate as amino acceptor. Hydroxypyruvate thus produced was used as donor substrate of transketolases from Escherichia coli or from Geobacillus stearothermophilus catalyzing the stereoselective formation of a carbon?carbon bond. The enzymatic cascade reaction was performed in one-pot in the presence of d-serine and appropriate aldehydes for the synthesis of valuable (3S)-hydroxyketones, which were obtained with high enantio- and diastereoselectivity and in good yield. The efficiency of the process was based on the irreversibility of both reactions allowing complete conversion of d-serine and aldehydes. (Figure presented.).
Selective Oxidation of Glycerol to Glyceric Acid in Base-Free Aqueous Solution at Room Temperature Catalyzed by Platinum Supported on Carbon Activated with Potassium Hydroxide
Tan, Hua,Tall, Omar E.,Liu, Zhaohui,Wei, Nini,Yapici, Tahir,Zhan, Tong,Hedhill, Mohamed Nejib,Han, Yu
, p. 1699 - 1707 (2016)
Pt supported on KOH-activated mesoporous carbon (K-AMC) was used to catalyze glycerol oxidation under base-free conditions at room temperature. To study the relationship between the carbon surface chemistry and the catalytic performance of the K-AMC-based Pt catalysts, different levels of surface oxygen functional groups (SOFGs) on the AMC supports were induced by thermal treatment at different temperatures under inert or H2 gas. A strong effect of the surface chemistry was observed on AMC-supported Pt catalysts for glycerol oxidation. The presence of carboxylic acid groups impedes the adsorption of glycerol, which leads to the reduction of catalytic activity, whereas the presence of high-desorption-temperature SOFGs, such as phenol, ether, and carbonyl/quinone groups, provide hydrophilicity to the carbon surface that improves the adsorption of glycerol molecules on Pt metal surface, which is beneficial for the catalytic activity.
Mg-Al mixed oxides supported bimetallic au-pd nanoparticles with superior catalytic properties in aerobic oxidation of benzyl alcohol and glycerol
Wang, Liang,Zhang, Wei,Zeng, Shangjing,Su, Dangsheng,Meng, Xiangju,Xiao, Fengshou
, p. 2189 - 2197 (2012)
Nano-sized Au and Pd catalysts are favorable for oxidations with molecular oxygen, and the preparation of this kind of nanoparticles with high catalytic activities is strongly desirable. We report a successful synthesis of bimetallic Au-Pd nanoparticles w
Role of the active site residues arginine-216 and arginine-237 in the substrate specificity of mammalian D-aspartate oxidase
Katane, Masumi,Saitoh, Yasuaki,Maeda, Kazuhiro,Hanai, Toshihiko,Sekine, Masae,Furuchi, Takemitsu,Homma, Hiroshi
, p. 467 - 476 (2011)
d-Aspartate oxidase (DDO) and d-amino acid oxidase (DAO) are flavin adenine dinucleotide-containing flavoproteins that catalyze the oxidative deamination of d-amino acids. Unlike DAO, which acts on several neutral and basic d-amino acids, DDO is highly specific for acidic d-amino acids. Based on molecular modeling and simulated annealing docking analyses, a recombinant mouse DDO carrying two substitutions (Arg-216 to Leu and Arg-237 to Tyr) was generated (R216L-R237Y variant). This variant and two previously constructed single-point mutants of mouse DDO (R216L and R237Y variants) were characterized to investigate the role of Arg-216 and Arg-237 in the substrate specificity of mouse DDO. The R216L-R237Y and R216L variants acquired a broad specificity for several neutral and basic d-amino acids, and showed a considerable decrease in activity against acidic d-amino acids. The R237Y variant, however, did not show any additional specificity for neutral or basic d-amino acids and its activity against acidic d-amino acids was greatly reduced. The kinetic properties of these variants indicated that the Arg-216 residue is important for the catalytic activity and substrate specificity of mouse DDO. However, Arg-237 is, apparently, only marginally involved in substrate recognition, but is important for catalytic activity. Notably, the substrate specificity of the R216L-R237Y variant differed significantly from that of the R216L variant, suggesting that Arg-237 has subsidiary effects on substrate specificity. Additional experiments using several DDO and DAO inhibitors also suggested the involvement of Arg-216 in the substrate specificity and catalytic activity of mouse DDO and that Arg-237 is possibly involved in substrate recognition by this enzyme. Collectively, these results indicate that Arg-216 and Arg-237 play crucial and subsidiary role(s), respectively, in the substrate specificity of mouse DDO.
The role of residues Arg169 and Arg220 in intersubunit interactions of yeast D-Amino acid oxidase
Cherskova,Khoronenkova,Tishkov
, p. 269 - 275 (2010)
D-Amino acid oxidase from the yeast Trigonopsis variabilis (EC 1.4.3.3, TvDAAO) exists as a dimer consisting of two identical subunits. The dimeric structure of the enzyme is stabilized by 12 (six pairs) hydrogen bonds, the residues Arg169 and Arg220 of each subunit being involved in eight hydrogen bonds. The Arg169Glu and Arg(169,220)Ala mutants of TvDAAO were prepared. Both mutant enzymes were expressed in E. coli cells as insoluble but catalytically active inclusion bodies. The introduction of amino acid substitutions at the intersubunit interface resulted in a change in the substrate specificity profile and a strong decrease in thermal stability.
Electrooxidation of glycerol on nickel and nickel alloy (Ni-Cu and Ni-Co) nanoparticles in alkaline media
Habibi, Biuck,Delnavaz, Nasrin
, p. 31797 - 31806 (2016)
In the present study, nickel (Ni) and Ni alloy (Ni-Cu and Ni-Co) nanoparticles modified carbon-ceramic electrodes (Ni/CCE, Ni-Cu/CCE and Ni-Co/CCE) were prepared by an electrochemical process for the oxidation of glycerol. In order to obtain the surface and physicochemical information, the Ni/CCE, Ni-Cu/CCE and Ni-Co/CCE were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and electrochemical techniques. Then, cyclic voltammetry and chronoamperometry were employed to characterize the electrocatalytic activity of the modified electrodes, Ni/CCE, Ni-Cu/CCE and Ni-Co/CCE, toward the oxidation of glycerol in 1.0 M NaOH solution. It was found that the Ni alloy nanoparticle modified electrodes are catalytically more active than the Ni/CCE, therefore, the alloying of the Ni with Cu and Co in the form of nanoparticles on the carbon-ceramic electrode, as a homemade substrate, greatly enhances the catalytic activity of the Ni-based electrocatalysts (as the non-platinum electrocatalysts) in glycerol oxidation.
SiO2-, Cu-, and Ni-supported Au nanoparticles for selective glycerol oxidation in the liquid phase
Kapkowski, Maciej,Bartczak, Piotr,Korzec, Mateusz,Sitko, Rafal,Szade, Jacek,Balin, Katarzyna,Lel?tko, Józef,Polanski, Jaroslaw
, p. 110 - 118 (2014)
We tested for the first time the efficiency of SiO2-, Cu-, and Ni-supported Au in deep glycerol oxidation in a diluted and viscous H2O2/H2O liquid phase. Acetic acid (AA), the C2 oxidate, was preferentially formed in such a system. High conversion (100%) and AA yields (90%) were observed for the sol-gel SiO2-supported Au in diluted solutions. Although with the increase of glycerol concentration in the viscous liquid phase these values decreased to ca. 40% (conversion) and 20% (AA yield), the addition of acetonitrile improved the AA yield to ca. 40%, while the surfactants were found to be capable of a many-fold enhancement of the catalyst activity at the room temperature highly viscous liquid phase. High performances were also observed for the bimetallic Au/Cu and Au/Ni catalysts obtained by nano-Au transfer; however, these catalysts were destroyed during the reaction by the Cu or Ni leaching effect.
Highly selective transformation of glycerol to dihydroxyacetone without using oxidants by a PtSb/C-catalyzed electrooxidation process
Lee, Seonhwa,Kim, Hyung Ju,Lim, Eun Ja,Kim, Youngmin,Noh, Yuseong,Huber, George W.,Kim, Won Bae
, p. 2877 - 2887 (2016)
We demonstrate an electrocatalytic reactor system for the partial oxidation of glycerol in an acidic solution to produce value-added chemicals, such as dihydroxyacetone (DHA), glyceraldehyde (GAD), glyceric acid (GLA), and glycolic acid (GCA). Under optimized conditions, the carbon-supported bimetallic PtSb (PtSb/C) catalyst was identified as a highly active catalyst for the selective oxidation of glycerol in the electrocatalytic reactor. The product selectivity can be strongly controlled as a function of the applied electrode potential and the catalyst surface composition. The main product from the electrocatalytic oxidation of glycerol was DHA, with a yield of 61.4% of DHA at a glycerol conversion of 90.3%, which can be achieved even without using any oxidants over the PtSb/C catalyst at 0.797 V (vs. SHE, standard hydrogen electrode). The electrocatalytic oxidation of biomass-derived glycerol represents a promising method of chemical transformation to produce value-added molecules.
Enzymatic synthesis of 'natural-labeled' 6-deoxy-L-sorbose precursor of an important food flavor
Hecquet,Bolte,Demuynck
, p. 8223 - 8232 (1996)
A biological route to natural 6-deoxy-L-sorbose is described. This method is based on the production of natural hydroxypyruvate and 4-deoxy-L-threose and their conversion into 6-deoxy-L-sorbose: hydroxypyruvate is obtained from L-serine by serine: glyoxylate aminotransferase catalysis, 4-deoxy-L-threose is obtained by microbial isomerization of 4-deoxy-L-erythrulose, this last being obtained from acetaldehyde (a naturally-available compound) and hydroxypyruvate by transketolase catalysis.
METHYLENEMALONIC ACID AND INTERMEDIATES, PROCESSES FOR THEIR PREPARATION AND ENGINEERED MICROORGANISMS
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Sheet 6, (2018/02/28)
The description relates to, inter alia, recombinant microorganisms, engineered metabolic pathways, chemical catalysts, and products produced through the use of the described methods and materials. The products produced include methylenemalonic acid and intermediates, as well as their salts and esters.