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Aldolase and N-Heterocyclic Carbene Gold(I) Catalysts: Compartmentalization and Immobilization on anionic clays for Concurrent Hybrid Catalysis at acidic pH. Catal Sci Technol 2023. [DOI: 10.1039/d2cy02056d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
One of the last limitation to concurrent reactions involving hybrid catalysis is pH. This has been solved by mixing a catalyst, operating at acidic pH, and an aldolase, through enzyme...
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One Step Forward in Exploration of Class II Pyruvate Aldolases Nucleophile and Electrophile Substrate Specificity. ChemCatChem 2021. [DOI: 10.1002/cctc.202100932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Biocatalysed synthesis of chiral amines: continuous colorimetric assays for mining amine-transaminases. Catal Sci Technol 2021. [DOI: 10.1039/d0cy02070b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Versatile and sensitive continuous colorimetric assays were developed for the high throughput screening of a large collection of amine-TAs from biodiversity, and allowed the discovery of a set of diverse biocatalysts with high synthetic potential.
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5
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Measurement of the Permanent Electric Dipole Moment of the Neutron. PHYSICAL REVIEW LETTERS 2020; 124:081803. [PMID: 32167372 DOI: 10.1103/physrevlett.124.081803] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating time-reversal invariance. The salient features of this experiment were the use of a ^{199}Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{n}=(0.0±1.1_{stat}±0.2_{sys})×10^{-26} e.cm.
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Pyruvate Aldolases Catalyze Cross-Aldol Reactions between Ketones: Highly Selective Access to Multi-Functionalized Tertiary Alcohols. ACS Catal 2020. [DOI: 10.1021/acscatal.9b05512] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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7
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Achiral Hydroxypyruvaldehyde Phosphate as a Platform for Multi-Aldolases Cascade Synthesis of Diuloses and for a Quadruple Acetaldehyde Addition Catalyzed by 2-Deoxyribose-5-Phosphate Aldolases. ACS Catal 2019. [DOI: 10.1021/acscatal.9b02668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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8
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2-Ketogluconate Kinase from Cupriavidus necator H16: Purification, Characterization, and Exploration of Its Substrate Specificity. Molecules 2019; 24:molecules24132393. [PMID: 31261738 PMCID: PMC6651773 DOI: 10.3390/molecules24132393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/21/2019] [Accepted: 06/27/2019] [Indexed: 11/30/2022] Open
Abstract
We have cloned, overexpressed, purified, and characterized a 2-ketogluconate kinase (2-dehydrogluconokinase, EC 2.7.1.13) from Cupriavidus necator (Ralstonia eutropha) H16. Exploration of its substrate specificity revealed that three ketoacids (2-keto-3-deoxy-d-gluconate, 2-keto-d-gulonate, and 2-keto-3-deoxy-d-gulonate) with structures close to the natural substrate (2-keto-d-gluconate) were successfully phosphorylated at an efficiency lower than or comparable to 2-ketogluconate, as depicted by the measured kinetic constant values. Eleven aldo and keto monosaccharides of different chain lengths and stereochemistries were also assayed but not found to be substrates. 2-ketogluconate-6-phosphate was synthesized at a preparative scale and was fully characterized for the first time.
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2-Deoxyribose-5-phosphate aldolase, a remarkably tolerant aldolase towards nucleophile substrates. Chem Commun (Camb) 2019; 55:7498-7501. [PMID: 31187106 DOI: 10.1039/c9cc03361k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We explored a collection of 2-deoxyribose-5-phosphate aldolases (DERAs) from biodiversity for their nucleophile substrate promiscuity. The DERAs were screened using as nucleophiles propanone, propanal, cyclobutanone, cyclopentanone, dihydroxyacetone, and glycolaldehyde with l-glyceraldehyde-3-phosphate as an electrophile in aldol addition. A DERA from Arthrobacter chlorophenolicus (DERAArthro) efficiently allowed the synthesis of the corresponding aldol adducts in good yields, displaying complementarity in terms of configuration and substrate specificity with fructose-6-phosphate aldolase, the only previously known aldolase with a large nucleophile tolerance.
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10
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Exploration of Aldol Reactions Catalyzed by Stereoselective Pyruvate Aldolases with 2‐Oxobutyric Acid as Nucleophile. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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11
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Sterile Neutrino Constraints from the STEREO Experiment with 66 Days of Reactor-On Data. PHYSICAL REVIEW LETTERS 2018; 121:161801. [PMID: 30387650 DOI: 10.1103/physrevlett.121.161801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/14/2018] [Indexed: 06/08/2023]
Abstract
The reactor antineutrino anomaly might be explained by the oscillation of reactor antineutrinos toward a sterile neutrino of eV mass. In order to explore this hypothesis, the STEREO experiment measures the antineutrino energy spectrum in six different detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this Letter, results from 66 days of reactor turned on and 138 days of reactor turned off are reported. A novel method to extract the antineutrino rates has been developed based on the distribution of the pulse shape discrimination parameter. The test of a new oscillation toward a sterile neutrino is performed by comparing ratios of cells, independent of absolute normalization and of the prediction of the reactor spectrum. The results are found to be compatible with the null oscillation hypothesis and the best fit of the reactor antineutrino anomaly is excluded at 97.5% C.L.
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Biocatalytic Aldol Addition of Simple Aliphatic Nucleophiles to Hydroxyaldehydes. ACS Catal 2018; 8:8804-8809. [PMID: 30221031 PMCID: PMC6135579 DOI: 10.1021/acscatal.8b02486] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/07/2018] [Indexed: 01/06/2023]
Abstract
Asymmetric aldol addition of simple aldehydes and ketones to electrophiles is a cornerstone reaction for the synthesis of unusual sugars and chiral building blocks. We investigated d-fructose-6-phosphate aldolase from E. coli (FSA) D6X variants as catalysts for the aldol additions of ethanal and nonfunctionalized linear and cyclic aliphatic ketones as nucleophiles to nonphosphorylated hydroxyaldehydes. Thus, addition of propanone, cyclobutanone, cyclopentanone, or ethanal to 3-hydroxypropanal or (S)- or (R)-3-hydroxybutanal catalyzed by FSA D6H and D6Q variants furnished rare deoxysugars in 8-77% isolated yields with high stereoselectivity (97:3 dr and >95% ee).
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Synthesis of Branched-Chain Sugars with a DHAP-Dependent Aldolase: Ketones are Electrophile Substrates of Rhamnulose-1-phosphate Aldolases. Angew Chem Int Ed Engl 2018. [PMID: 29542859 DOI: 10.1002/anie.201712851] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dihydroxyacetone phosphate (DHAP)-dependent rhamnulose aldolases display an unprecedented versatility for ketones as electrophile substrates. We selected and characterized a rhamnulose aldolase from Bacteroides thetaiotaomicron (RhuABthet) to provide a proof of concept. DHAP was added as a nucleophile to several α-hydroxylated ketones used as electrophiles. This aldol addition was stereoselective and produced branched-chain monosaccharide adducts with a tertiary alcohol moiety. Several aldols were readily obtained in good to excellent yields (from 76 to 95 %). These results contradict the general view that aldehydes are the only electrophile substrates for DHAP-dependent aldolases and provide a new C-C bond-forming enzyme for stereoselective synthesis of tertiary alcohols.
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Synthesis of Branched-Chain Sugars with a DHAP-Dependent Aldolase: Ketones are Electrophile Substrates of Rhamnulose-1-phosphate Aldolases. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712851] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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15
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Stereoselective synthesis of γ-hydroxy-α-amino acids through aldolase-transaminase recycling cascades. Chem Commun (Camb) 2018; 53:5465-5468. [PMID: 28466909 DOI: 10.1039/c7cc00742f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Efficient bi-enzymatic cascades combining aldolases and α-transaminases were designed for the synthesis of γ-hydroxy-α-amino acids. These recycling cascades provide high stereoselectivity, atom economy, and an equilibrium shift of the transamination. l-syn or anti-4-hydroxyglutamic acid and d-anti-4,5-dihydroxynorvaline were thus prepared in 83-95% yield in one step from simple substrates.
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Transketolase-Aldolase Symbiosis for the Stereoselective Preparation of Aldoses and Ketoses of Biological Interest. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700209] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Breaking the Dogma of Aldolase Specificity: Simple Aliphatic Ketones and Aldehydes are Nucleophiles for Fructose-6-phosphate Aldolase. Chemistry 2017; 23:5005-5009. [DOI: 10.1002/chem.201701020] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 01/12/2023]
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18
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Insights into the Thiamine Diphosphate Enzyme Activation Mechanism: Computational Model for Transketolase Using a Quantum Mechanical/Molecular Mechanical Method. Biochemistry 2016; 55:2144-52. [PMID: 26998737 DOI: 10.1021/acs.biochem.5b00787] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We propose the first computational model for transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, using a quantum mechanical/molecular mechanical method on the basis of crystallographic TK structures from yeast and Escherichia coli, together with experimental kinetic data reported in the literature with wild-type and mutant TK. This model allowed us to define a new route for ThDP activation in the enzyme environment. We evidenced a strong interaction between ThDP and Glu418B of the TK active site, itself stabilized by Glu162A. The crucial point highlighted here is that deprotonation of ThDP C2 is not performed by ThDP N4' as reported in the literature, but by His481B, involving a HOH688A molecule bridge. Thus, ThDP N4' is converted from an amino form to an iminium form, ensuring the stabilization of the C2 carbanion or carbene. Finally, ThDP activation proceeds via an intermolecular process and not by an intramolecular one as reported in the literature. More generally, this proposed ThDP activation mechanism can be applied to some other ThDP-dependent enzymes and used to define the entire TK mechanism with donor and acceptor substrates more accurately.
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Observation of Gravitationally Induced Vertical Striation of Polarized Ultracold Neutrons by Spin-Echo Spectroscopy. PHYSICAL REVIEW LETTERS 2015; 115:162502. [PMID: 26550870 DOI: 10.1103/physrevlett.115.162502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Indexed: 06/05/2023]
Abstract
We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a |B0|=1 μT magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an excellent method by which to reconstruct the energy spectrum of a confined ensemble of neutrons. The method takes advantage of the relative dephasing of spins arising from a gravitationally induced striation of stored UCNs of different energies, and also permits an improved determination of the vertical magnetic-field gradient with an exceptional accuracy of 1.1 pT/cm. This novel combination of a well-known nuclear resonance method and gravitationally induced vertical striation is unique in the realm of nuclear and particle physics and should prove to be invaluable for the assessment of systematic effects in precision experiments such as searches for an electric dipole moment of the neutron or the measurement of the neutron lifetime.
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Highly stable atomic vector magnetometer based on free spin precession. OPTICS EXPRESS 2015; 23:22108-22115. [PMID: 26368184 DOI: 10.1364/oe.23.022108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a magnetometer based on optically pumped Cs atoms that measures the magnitude and direction of a 1 μT magnetic field. Multiple circularly polarized laser beams were used to probe the free spin precession of the Cs atoms. The design was optimized for long-time stability and achieves a scalar resolution better than 300 fT for integration times ranging from 80 ms to 1000 s. The best scalar resolution of less than 80 fT was reached with integration times of 1.6 to 6 s. We were able to measure the magnetic field direction with a resolution better than 10 μrad for integration times from 10 s up to 2000 s.
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Genome Mining for Innovative Biocatalysts: New Dihydroxyacetone Aldolases for the Chemist’s Toolbox. ChemCatChem 2015. [DOI: 10.1002/cctc.201500014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Engineering a Thermostable Transketolase for Unnatural Conversion of (2S
)-Hydroxyaldehydes. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500207] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Straightforward Synthesis of Terminally Phosphorylated L
-Sugars via
Multienzymatic Cascade Reactions. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500190] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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l-Rhamnulose-1-phosphate and l-fuculose-1-phosphate aldolase mediated multi-enzyme cascade systems for nitrocyclitol synthesis. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2014.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Thermostable Transketolase fromGeobacillus stearothermophilus:Characterization and Catalytic Properties. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201200590] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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28
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One-Pot Cascade Reactions using Fructose-6-phosphate Aldolase: Efficient Synthesis of D-Arabinose 5-Phosphate, D-Fructose 6-Phosphate and Analogues. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201200150] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Efficient Immobilization of Yeast Transketolase on Layered Double Hydroxides and Application for Ketose Synthesis. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201000925] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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30
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A Mutant D-Fructose-6-Phosphate Aldolase (Ala129Ser) with Improved Affinity towards Dihydroxyacetone for the Synthesis of Polyhydroxylated Compounds. Adv Synth Catal 2010. [DOI: 10.1002/adsc.200900772] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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Fluorogenic substrates for the screening assay of transketolase through beta-elimination of umbelliferone—Development, scope and limitations. J Biotechnol 2010; 145:359-66. [DOI: 10.1016/j.jbiotec.2009.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 11/23/2009] [Accepted: 12/31/2009] [Indexed: 10/20/2022]
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32
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Amino acid precursors for the detection of transketolase activity in Escherichia coli auxotrophs. Bioorg Med Chem Lett 2009; 19:3767-70. [DOI: 10.1016/j.bmcl.2009.04.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/21/2009] [Accepted: 04/22/2009] [Indexed: 10/20/2022]
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34
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35
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Synthesis of stereochemical probes for new fluorogenic assays for yeast transketolase variants. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.02.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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