- SELECTIVE VALORIZATION OF BIOMASS SUGARS
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Disclosed are methods of forming an epimer or a dehydrated isomer of a pyranose monosaccharide or a pyranose saccharide residue in an oligosaccharide or a glycoside.
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Page/Page column 23; 33; 42
(2021/06/26)
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- Probing substrate promiscuity of amylosucrase from neisseria polysaccharea
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The amylosucrase from Neisseria polysaccharea (NpAS) naturally catalyzes the synthesis of a variety of products from sucrose and shows signs of plasticity of its active site. To explore further this promiscuity, the tolerance of amylosucrase towards different donor and acceptor substrates was investigated. The selection of alternate donor substrates was first made on the basis of preliminary molecular modeling studies. From 11 potential donors harboring selective derivatizations that were experimentally evaluated, only p-nitrophenyl-α-D-glucopyranoside was used by the wild-type enzyme, and this underlines the high specificity of the -1 subsite of NpAS for glucosyl donor substrates. The acceptor substrate promiscuity was further explored by screening 20 hydroxylated molecules, including D- and L-monosaccharides as well as polyols. With the exception of one compound, all were successfully glucosylated, and this showcases the tremendous plasticity of the +1 subsite of NpAS, which is responsible for acceptor recognition. The products obtained from the transglucosylation reactions of three selected acceptors were characterized, and they revealed original structures and enzyme enantiopreference, which were more particularly analyzed by insilico docking analyses.
- Daude, David,Champion, Elise,Morel, Sandrine,Guieysse, David,Remaud-Simeon, Magali,Andre, Isabelle
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supporting information
p. 2288 - 2295
(2013/08/23)
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- Synthesis of galacto-and mannosucroses
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A concise synthesis of β-D-fructofuranosyl α-D-galactopyranoside (2), and β-D-fructofuranosyl α-D-mannopyranoside (3) is described. Inversion of the C-3 α-hydroxy group of α-D-galactopyranosyl and α-D-mannopyranosyl β-dpsicofuranosides 10 and 11 via oxida
- Ueda, Atsushi,Yamashita, Takanori,Uenishi, Jun'ichi
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experimental part
p. 1711 - 1720
(2011/04/15)
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- Method for synthesizing oligosaccharides and glycosylation
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The invention relates to an enzymatic method for synthesizing oligosaccharides, whereby one saccharide group of a sucrose analogue each is transferred onto an acceptor molecule, for example for glycosylating a hydroxyl compound, a saccharide, peptide, or a drug. According to the inventive method, an enzymatic synthesis of β-D-fructofuranosyl-a-D-aldopyranoside is carried out in a first step, and in a second step one of the saccharide groups is enzymatically transferred onto the acceptor molecule.
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Page/Page column 5-6
(2009/04/24)
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- Synthesis of sucrose analogues and the mechanism of action of Bacillus subtilis fructosyltransferase (levansucrase)
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In the present study, we have coupled detailed acceptor and donor substrate studies of the fructosyltransferase (FTF, levansucrase) (EC 2.4.1.162) from Bacillus subtilis NCIMB 11871, with a structural model of the substrate enzyme complex in order to investigate in detail the roles of the active site amino acids in the catalytic action of the enzyme and the scope and limitation of substrates. Therefore we have isolated the ftf gene, expressed in Escherichia coli, yielding a levansucrase. Consequently, detailed acceptor property effects in the fructosylation by systematic variation of glycoside acceptors with respect to the positions (2, 3, 4 and 6) of the hydroxyl groups from equatorial to axial have been studied for preparative scale production of new oligosaccharides. Such investigations provided mechanistic insights of the FTF reaction. The configuration and the presence of the C-2 and C-3 hydroxyl groups of the glucopyranoside derivatives either as substrates or acceptors have been identified to be rate limiting for the trans-fructosylation process. The rates are rationalized on the basis of the coordination of d-glycopyranoside residues in 4C1 conformation with a network of amino acids by Arg360, Tyr411, Glu342, Trp85, Asp247 and Arg246 stabilization of both acceptors and substrates. In addition we also describe the first FTF reaction, which catalyzes the β-(1→2)-fructosyl transfer to 2-OH of l-sugars (l-glucose, l-rhamnose, l-galactose, l-fucose, l-xylose) presumably in a 1C4 conformation. In those conformations, the l-glycopyranosides are stabilized by the same hydrogen network. Structures of the acceptor products were determined by NMR and mass spectrometry analysis.
- Seibel, Juergen,Moraru, Roxana,Goetze, Sven,Buchholz, Klaus,Na'amnieh, Shukrallah,Pawlowski, Alice,Hecht, Hans-Juergen
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p. 2335 - 2349
(2007/10/03)
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- Biocatalytic and chemical investigations in the synthesis of sucrose analogues
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Herein, we report about the synthesis of sucrose analogues, obtained by two different approaches: a chemical and an enzymatic. The one step synthesis of the sucrose analogues with the exo-fructosyltransferase (EC 2.4.1.162) from Bacillus subtilis NCIMB 11871, which transfers the fructosyl residue of the substrate sucrose to the monosaccharide acceptors galactose, mannose, xylose and fucose, has been developed. Effects in the fructosylation by variation of the positions of the hydroxyl-groups in glycopyranoside acceptors have been studied in respect to their acceptor properties. In contrast, the chemical equivalent nonenzymatic organic synthesis of galacto-sucrose and manno-sucrose has been achieved including six synthetic steps.
- Seibel, Jürgen,Moraru, Roxana,G?tze, Sven
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p. 7081 - 7086
(2007/10/03)
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- The Donor Substrate Spectrum of Recombinant Sucrose Synthase 1 from Potato for the Synthesis of Sucrose Analogues
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The donor substrate spectrum of recombinant sucrose synthase 1 (SuSy1) from potato was studied in order to synthesise novel sucrose analogues. With D-fructose as acceptor substrate SuSy1 accepts a variety of UDP-activated sugars, e.g., UDP-N-acetyl-α-D-glucosamine (UDP-GlcNAc, 2) (100%), UDP-α-D-glucuronic acid (UDP-GlcA, 3) (32%), UDP-α-D-xylose (UDP-Xyl, 4) (39%), UDP-α-D-galactose (UDP-Gal, 5) (23%), and UDP-N-acetyl-α-D-galactosamine (UDP-GalNAc, 6) (23%). The kinetic analyses revealed that the non-natural donors 2 (kcat/Km 1.2 s-1 mM-1) and 5 (kcat/Km 0.01 s-1 mM-1) were relative poor substrates compared to UDP-Glc 1 (kcat/Km 310.4 s-1 mM-1). UDP-GlcNAc was used in a preparative synthesis to produce 188 mg (0.5 mmol) 2-acetamido-2-deoxy-D-glucopyranosyl-β-D-fructofuranoside (9). The sucrose analogue 9 was not hydrolysed by invertase.
- R?mer, Ulrike,Rupprath, Carsten,Elling, Lothar
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p. 684 - 686
(2007/10/03)
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- Sucrochemistry. Part 33. The Selective Pivaloylation of Sucrose
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The pivaloylation of sucrose by pivaloyl chloride (2,2-dimethylpropanoyl chloride) has been studied under the variety of conditions and shown to be selective for certain hydroxy groups.There exist two principal, but divergent reaction pathways lying betwe
- Chowdhary, Manjit S.,Hough, Leslie,Richardson, Anthony C.
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p. 419 - 427
(2007/10/02)
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- α-D-ALLOPYRANOSYL β-D-FRUCTOFURANOSIDE (allo-SUCROSE) AND ITS DERIVATIVES
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Reduction of 3-ketosucrose (1) with sodium borohydride gave mainly α-D-allopyranosyl β-D-fructofuranoside (2), characterised as its octabenzoate.Using sodium borodeuteride, allo-sucrose (5) and sucrose (6) were obtained in the ratio 12:1.The mixture was fractionated on Dowex-50 X8 resin , and the derivatives were isolated as their octa-acetates.Inspection of the (13)C-n.m.r. spectra of 5 and 6 enabled the C-3 signals to be assigned, allo-Sucrose (2) was more readily obtained by oxidation of sucrose with dimethyl sulphoxide-acetic anhydride followed by reduction with sodium borohydride and fractionation on Dowex-50 X8 resin.Tritylation of 2 followed by acetylation gave, after chromatography, the 6,1',6'-tritrityl ether (9, 10percent), the 6,6'-ditrityl ether (10, 26percent), and a mixture of monotrityl ethers (20percent).Hydrogenolysis of 9 and 10 gave the penta-acetate and hexa-acetate, respectively, with no detectable migration of AcO-4.Treatment of 2 with sulphuryl chloride at -50 degC gave the 6,6'-dichloride.
- Hough, Leslie,O'Brien, Eugene
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