5650-40-8Relevant academic research and scientific papers
Carboligation reactions mediated by benzoylformate decarboxylase immobilized on a magnetic solid support
Tural, Bilsen,Tural, Servet,Demir, Ayhan S.
, p. 415 - 421 (2013)
In this study, magnetic nanoparticles (Fe3O4, magnetite) with immobilized metal affinity ligands (MSS) were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), and vibrating-sample magnetometer (VSM) methods for purification and immobilization of the histidine-tagged recombinant benzoylformate decarboxylase (BFD). The MSS support was shown to be eligible for selective binding of HIS-tagged BFD by SDS-page analysis. Loading capacity of the MSS support was determined as 43.6 ± 1.1 mg/g. The regeneration ability for protein binding was also studied. An immobilized BFD was tested to catalyze benzoin condensation and representative cross acyloin reaction. Conversion and enantiomeric excess values were comparable with that of free enzyme catalyzed reactions. Chirality 25:415-421, 2013.
Stereochemistry of the Asymmetric Oxidation of Ketone Enolates Using (Camphorylsulfonyl)oxaziridines
Davis, Franklin A.,Haque, Serajul M.
, p. 4083 - 4085 (1986)
Asymmetric oxidation of the sodium enolates of ketones using chiral oxaziridines (+)-(2R,8aS)-1 and (-)-(2S,8aR)-2 affords α-hydroxy ketones 4 in high optical purity (69-95percent ee).An open transition state, controlled by nonbonded steric interactions, is proposed as being responsible for the chiral recognition.
Asymmetric oxidation of silyl enol ethers using chiral dioxiranes derived from α-fluoro cyclohexanones
Solladié-Cavallo,Lupattelli,Jierry,Bovicelli,Angeli,Antonioletti,Klein
, p. 6523 - 6526 (2003)
Asymmetric oxidation of silyl enolethers derived from tetralone, 2-methyl-tetralone, propiophenone and deoxybenzoin using chiral dioxiranes generated in situ from oxone and new chiral α-fluorinated cyclohexanones or fructose-derived ketone have been studied. It was observed that tetrasubstituted silyl enolethers are poor substrates, that substitution at C8 of the fluoro-ketones has a significant effect on the enantioselectivities obtained and that the fructose-derived-ketone provides higher enantioselectivities. The absolute configuration of the major hydroxy ketones obtained can be rationalized using a spiro model proposed for epoxidation of olefins.
Enantioselective C - C bond ligation using recombinant Escherichia coli-whole-cell biocatalysts
De Maria, Pablo Dominguez,Stillger, Thomas,Pohl, Martina,Kiesel, Michael,Liese, Andreas,Groeger, Harald,Trauthwein, Harald
, p. 165 - 173 (2008)
Thiamine diphosphate (ThDP)-dependent enzymes like benzaldehyde lyase from Pseudomonas fluorescens (BAL) and benzoylformate decarboxylase from Pseudomonas putida (BFD) are versatile biocatalysts for the C - C bond ligation of aldehydes to form enantiomerically pure 2-hydroxy ketones. However, the large-scale application of this enzyme class is often restricted by the required external addition of the expensive cofactor ThDP, as well as by the common use of dimethyl sulfoxide (DMSO) as a cosolvent, which leads to problems during the work-up procedure. In the present paper we demonstrate that the addition of the excess cofactors, ThDP and magnesium ions (Mg2+), is not required when BAL or BFD are used in Escherichia coli resting cells. Furthermore, the combination of these resting cells with a biphasic reaction medium [methyl tert-butyl ether (MTBE)/aqueous buffer] allows an increase of the substrate concentration up to 1M, and an efficient extractive work-up. As a practical example, e.g., the synthesis of (R)-2-hydroxy-3,3-dimethoxy-phenylpropanone from benzaldehyde and 2,2-dimethoxyacetaldehyde was optimized, achieving an isolated yield of 78 %, and an enantiomeric excess of 98% ee in 24 h when operating at a substrate concentration of 0.4 M. The described reaction system in a biphasic medium is suitable for a wide range of aldehydes as substrates. The biphasic reaction medium minimizes also the formation of by-products, which were observed when this reaction was performed in the conventional DMSO/buffer system.
Covalent immobilization of benzoylformate decarboxylase from Pseudomonas putida on magnetic epoxy support and its carboligation reactivity
Tural, Bilsen,Tarhan, Tuba,Tural, Servet
, p. 188 - 194 (2014)
Epoxy attached magnetic nanoparticles were prepared and used as solid support for covalent immobilization and stabilization of benzoylformate decarboxylase (BFD, E.C. 4.1.1.7) from Pseudomonas putida. A three-step immobilization/stabilization procedure is applied. The enzyme is firstly covalently immobilized under mild experimental conditions (e.g. pH 7.0, no added MgSO4 and 20 C). Secondly, the enzyme is immobilized under more drastic conditions (higher pH values, higher ionic strengths, etc.) to facilitate an increase in effective concentration of the enzyme on the support near the epoxide reactive sites. Thirdly, the remaining epoxy groups are blocked to stop any additional interaction between the enzyme and the support. With more drastic conditions, the loading of enzyme can be increased from 1.25 to 6.70 mg enzyme per gram of support. The covalently bounded enzyme was characterized in terms of its activity and stability for the formation of (S)-2-hydroxypropiophenone (2-HPP). The activity of the immobilized BFD was determined to be 53.0% related to the activity of the free enzyme. The immobilized biocatalyst retained 95% of its original activity after five reaction cycles.
Immobilization of benzaldehyde lyase and its application as a heterogeneous catalyst in the continuous synthesis of a chiral 2-hydroxy ketone
Kurlemann, Nils,Liese, Andreas
, p. 2955 - 2958 (2004)
Hexahistidine-tagged benzaldehyde lyase from E. coli SG13009/BAL HIS was immobilized by means of metal ion affinity binding to a nickel(II)-nitrilotriacetic acid derivatized carrier and applied as a heterogeneous biocatalyst in the synthesis of (R)-2-hydroxy-1-phenyl-propanone. The applicability of the immobilization by metal ion affinity binding was proven in repetitive batch reactions and in a continuously operated plug flow reactor.
Fluorescence spectroscopy as a novel method for on-line analysis of biocatalytic C-C bond formations
Kara, Selin,Anton, Fabienne,Solle, Doerte,Neumann, Markus,Hitzmann, Bernd,Scheper, Thomas,Liese, Andreas
, p. 124 - 129 (2010)
On-line analysis of bioprocesses is of increasing interest avoiding the time delay for off-line sample preparation and the following analyses via chromatographic methods. Moreover, continuous monitoring of the reaction components during chemo- or biocatalytic transformations provides a direct control of the process. Since productivity of the processes can be controlled simultaneously, on-line monitoring of the processes is attractive for industrial applications. The reliable in situ monitoring of biocatalyzed reactions has been a challenge where reactions run in aqueous solutions. Limited work has been published on the use of spectroscopic methods for on-line analysis of biocatalytic reactions up to now. However, in this communication two dimensional (2D)-fluorescence spectroscopy has been proved to be an effective tool for on-line monitoring of the carboligation reactions catalyzed by wild type benzoylformate decarboxylase (BFD) from Pseudomonas putida. BFD is a thiamine diphosphate (ThDP)-dependent enzyme that catalyzes the asymmetric C-C bond formation to (S)-2-hydroxypropiophenone ((S)-2-HPP) starting from benzaldehyde and acetaldehyde. The analysis of the fluorescence spectra was achieved by chemometric modeling performing principle component analysis (PCA) and partial least square (PLS) regression. The derived chemometric models were used for the validation of concentrations of yielded 2-HPP and the substrate benzaldehyde with low root mean square error of calibration (RMSEC).
Carboligation reactions with benzaldehyde lyase immobilized on superparamagnetic solid support
Sopaci, S. Betuel,Simsek, Ilke,Tural, Bilsen,Volkan, Muervet,Demir, Ayhan S.
, p. 1658 - 1664 (2009)
Histidine-tagged recombinant benzaldehyde lyase (BAL, EC 4.1.2.38) was efficiently immobilized to surface-modified magnetic particles with affinity ligand binding. In addition to conventional benzoin condensation reactions, two important representative BAL-catalyzed carboligation reactions, were also performed with this magnetically responsive biocatalyst. The results obtained from the carboligation reactions that were performed with this simple and convenient heterogenous biocatalyst were comparable to that of free-enzyme-catalyzed reactions.
Carboligation reactivity of benzaldehyde lyase (BAL, EC 4.1.2.38) covalently attached to magnetic nanoparticles
Tural, Bilsen,Simsek, Ilke,Tural, Servet,Celebi, Buelent,Demir, Ayhan S.
, p. 260 - 268 (2013)
Epoxy-functionalized Fe3O4-SiO2 core-shell magnetic nanoparticles (epoxy-M-support) were prepared by modification with glycidyloxypropyltrimethoxysilane (GPTMS) and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR) methods. Pure histidine-tagged recombinant benzaldehydelyase (BAL, EC 4.1.2.38) was efficiently immobilized onto the epoxy-M-support with covalent binding. An immobilized BAL epoxy-M-support system was tested to catalyze the self and cross condensation reactions of aldehydes, and the kinetic resolution of racemic acyloins. The acyloin products were obtained in high yield and with high enantiomeric excesses (≥98% ee). The carboligation reactivity of the immobilized enzyme was comparable to that of free enzyme-catalyzed reactions. The covalent immobilization offers high enzyme activity and stability (at least 5 repeats without losing its activity).
Enantioselective synthesis of hydroxy ketones through cleavage and formation of acyloin linkage. Enzymatic kinetic resolution via C-C bond cleavage
Demir,Pohl,Janzen,Mueller
, p. 633 - 635 (2001)
Both enantiomers of benzoins and (R)-2-hydroxy-1-phenylpropanone analogues were obtained in high yield on a preparative scale starting from aromatic aldehydes, rac-benzoins and aliphatic aldehydes via enzyme-catalysed C-C bond cleavage and C-C bond formation reactions.
