The Experts below are selected from a list of 10134 Experts worldwide ranked by ideXlab platform
Tony D. James - One of the best experts on this subject based on the ideXlab platform.
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“Click-fluors”: triazole-linked Saccharide sensors
Organic Chemistry Frontiers, 2016Co-Authors: Wenlei Zhai, Tony D. James, Brette M. Chapin, Akina Yoshizawa, Hui Chen Wang, Stephen A. Hodge, Eric V. Anslyn, John S. FosseyAbstract:A series of boronic acid-containing Saccharide receptors was synthesised via copper catalysed azide–alkyne cycloaddition (CuAAC) reactions. Their Saccharide binding capacity was studied by 1H and 11B NMR spectroscopy titrations and isothermal titration calorimetry (ITC) techniques. Fluorescent sensors were generated by linking a phenylboronic acid (PBA) receptor with fluorophores via a triazole-linker. Fluorescence titrations with fructose revealed that the substitution pattern about the PBA influences the fluorescence response to Saccharides. Titrations studied by 1H NMR spectroscopy suggested that fructose binding is enhanced when the aromatic ring bearing the boronic acid has the triazole-containing substituent at the ortho position. No evidence of either a dative N–B bond or solvent insertion (between B and N) was observed by 11B NMR spectroscopy. These results demonstrate that synthetic accessible triazole receptors may allow rapid sensor synthesis, screening and discovery.
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boronic acids in Saccharide recognition
2006Co-Authors: Tony D. James, Marcus D Phillips, Seiji ShinkaiAbstract:1: Introduction 2: The Molecular Recognition of SaccharideS 2.1: Molecular Recognition 2.2: The Importance of Saccharides 2.3: Non-Boronic Acid Appended Synthetic Sensors for Saccharides 3: Complexation of Boronic Acids with Saccharides 3.1: A Brief History 3.2: Acidity and the O-B-O Bond Angle 3.3: Complex Formation and Dependence on pH 3.4: Binding Constants and the Influence of Lewis Bases 4: Fluorescent Sensors 4.1: The Application of Fluorescence in Sensing 4.2: Photoexcitation and Subsequent Relaxation 4.3: Excited State Internal Charge Transfer (ICT) 4.4: Fluorescent Internal Charge Transfer (ICT) Sensory Systems 4.5: Excited State Photoinduced Electron Transfer (PET) 4.6: Photoinduced Electron Transfer (PET) Sensory Systems 4.7: Ditopic Sensors 4.8: Other Fluorescent Sensors 4.9: Amine - Boron (N-B) Interactions 4.10: The Importance of Pyranose to Furanose Interconversion 4.11: Summary 5: Modular Fluorescent Sensors 5.1: The Design Rationale 5.2: Modular Systems 5.3: Energy Transfer Systems 5.4: Fluorophore Dependence in Modular Systems 5.5: Other approaches 5.6: Summary 6: Other types of sensor 6.1: Colorimetric sensors 6.2: Electrochemical Sensors 6.3: Assay Systems 6.4: Polymer and Surface Bound Sensors 6.5: Odds and Ends 7: OTHER SYSTEMS FOR Saccharide RECOGNITION 7.1: Receptors at the Air-Water Interface 7.2: Transport and Extraction 7.3: CD Receptors 7.4: Molecular Imprinting 8: Conclusions 9: Bibliography
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Artificial Receptors as Chemosensors for Carbohydrates
Host-Guest Chemistry, 2001Co-Authors: Tony D. James, Seiji ShinkaiAbstract:As the chemistry of Saccharides and related molecular species plays a significant role in the metabolic pathways of living organisms, detecting the presence and concentration of biologically important sugars in aqueous solution is necessary in a variety of medicinal and industrial contexts. The recognition of d-glucose is of particular interest, for example in the monitoring of diabetics. Recent research provides clear evidence that tight control of blood sugar levels in diabetics sharply reduces the risk of long term complications, which include blindness, kidney failure, heart attacks and even gangrene and amputation of the limbs. Current enzymatic detection methods of sugars offer specificity for only a few Saccharides; additionally, enzyme based sensors are unstable in harsh conditions. Phenylboronic acid has been known for 120 years. However, it took until 1959 for the first quantitative evaluation of Saccharide boronic acid interactions. Boronic acids react with 1,2 or 1,3 diols of Saccharides to form five- or six-membered cyclic esters in non-aqueous or basic aqueous media. The stable boronic acid-based Saccharide receptors offer the possibility of creating Saccharide sensors ‘chemosensors’ which are selective and sensitive for any chosen Saccharide.
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Fluorescent internal charge transfer (ICT) Saccharide sensor
Tetrahedron Letters, 2001Co-Authors: Susumu Arimori, Laurence I. Bosch, Christopher J. Ward, Tony D. JamesAbstract:An efficient internal charge transfer (ICT) fluorescent Saccharide sensor 3 has been prepared from 2-formyl benzeneboronic acid and aniline. When Saccharides interact with sensor 3 in aqueous solution at pH 8.21 the emission maxima at 404 nm shifts to 362 nm.
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novel Saccharide photoinduced electron transfer sensors based on the interaction of boronic acid and amine
Journal of the American Chemical Society, 1995Co-Authors: Tony D. James, K Samankumara R A Sandanayake, Ritsuko Iguchi, Seiji ShinkaiAbstract:Two boronic acid systems, monoboronic acid 3 and diboronic acid 8, were synthesized. When Saccharides form cyclic boronate esters with these boronic acids, the Lewis acid-base interaction between the boronic acid moiety and tertiary amine is strengthened; when Saccharides form cyclic boronate esters with boronic acids the acidity of the boronic acid is enhanced. The strength of this acid-base interaction modulates the photoinduced electron transfer (PET) from the amine to anthracene. Both of these compounds show increased fluoresecence at pH 7.77 through supression of the photoinduced electron transfer from nitrogen to anthracene on Saccharide binding, a direct result of the stronger boron-nitrogen bond. Compound 3 shows the typical selectivity of monoboronic acids towards Saccharides. Compound 8 which has a cleftlike structure is particularly selective and sensitive for, glucose due to the formation of an intramolecular 1:1 complex between the two boronic acids and the 1,2- and 4,6-hydroxyls of glucose. This is the first example in which ditopic recognition of monoSaccharides is achieved in a PET sensor system.
Norio Shiomi - One of the best experts on this subject based on the ideXlab platform.
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Three novel oligoSaccharides synthesized using Thermoanaerobacter brockii kojibiose phosphorylase
Chemistry Central Journal, 2007Co-Authors: Natsuko Takahashi, Tomoyuki Nishimoto, Eri Fukushi, Shuichi Onodera, Jun Kawabata, Noureddine Benkeblia, Norio ShiomiAbstract:Background Recently synthesized novel oligoSaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligoSaccharides using kojibiose phosphorylase. Results Three novel oligoSaccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to xylosylfructoside [ O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside] using Thermoanaerobacter brockii kojibiose phosphorylase. These oligoSaccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural characterisation. The ^1H and ^13C NMR signals of each Saccharide were assigned using 2D-NMR including COSY (correlated spectroscopy), HSQC (herteronuclear single quantum coherence), CH_2-selected E-HSQC (CH_2-selected Editing-HSQC), HSQC-TOCSY (HSQC-total correlation spectroscopy) and HMBC (heteronuclear multiple bond correlation). Conclusion The structure of three synthesized Saccharides were determined, and these oligoSaccharides have been identified as O -α-D-glucopyranosyl-(1→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 1 ), O -α-D-glucopyranosyl-(1→2)- O -α-D-glucopyranosyl-(1→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 2 ) and O -α-D-glucopyranosyl-(1→[2- O -α-D-glucopyranosyl-1]_2→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 3 ).
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three novel oligoSaccharides synthesized using thermoanaerobacter brockii kojibiose phosphorylase
Chemistry Central Journal, 2007Co-Authors: Natsuko Takahashi, Tomoyuki Nishimoto, Eri Fukushi, Shuichi Onodera, Jun Kawabata, Noureddine Benkeblia, Norio ShiomiAbstract:Recently synthesized novel oligoSaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligoSaccharides using kojibiose phosphorylase. Three novel oligoSaccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to xylosylfructoside [O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside] using Thermoanaerobacter brockii kojibiose phosphorylase. These oligoSaccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural characterisation. The 1H and 13C NMR signals of each Saccharide were assigned using 2D-NMR including COSY (correlated spectroscopy), HSQC (herteronuclear single quantum coherence), CH2-selected E-HSQC (CH2-selected Editing-HSQC), HSQC-TOCSY (HSQC-total correlation spectroscopy) and HMBC (heteronuclear multiple bond correlation). The structure of three synthesized Saccharides were determined, and these oligoSaccharides have been identified as O-α-D-glucopyranosyl-(1→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 1), O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl-(1→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 2) and O-α-D-glucopyranosyl-(1→[2-O-α-D-glucopyranosyl-1]2→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 3).
Tsuyoshi Minami - One of the best experts on this subject based on the ideXlab platform.
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Data_Sheet_1_A Saccharide Chemosensor Array Developed Based on an Indicator Displacement Assay Using a Combination of Commercially Available Reagents.pdf
2019Co-Authors: Yui Sasaki, Zhoujie Zhang, Tsuyoshi MinamiAbstract:Herein, a very simple colorimetric chemosensor array is reported for Saccharides (D-glucose, D-fructose, D-xylose, D-galactose, D-mannose, L-rhamnose, and N-acetyl-D-gluosamine). While various types of chemosensors for Saccharides have been investigated extensively to-this-date, tremendous additional efforts are still required on a regular basis for the syntheses of new chemosensors. Complicated syntheses would be a bottleneck, given that artificial receptor-based chemosensing systems are not so popular in comparison to biomaterial-based (e.g., enzyme-based) sensing systems. Toward this end, chemosensor array systems using molecular self-assembled materials can avoid the abovementioned synthetic efforts and achieve simultaneous qualitative and quantitative detection of a number of guest Saccharides. Using a practical approach, we focus on an indicator displacement assay (IDA) to fabricate a chemosensor array for colorimetric Saccharide sensing. On this basis, 3-nitrophenylboronic acid (3-NPBA) spontaneously reacts with catechol dyes such as alizarin red S (ARS), bromopyrogallol red (BPR), pyrogallol red (PR), and pyrocatechol violet (PV), and yields boronate ester derivatives with color changes. The addition of Saccharides into the aqueous solution of the boronate esters induces color recovery owing to the higher binding affinity of 3-NPBA for Saccharides, thus resulting in the release of dyes. By employing this system, we have succeeded in discriminating Saccharides qualitatively and quantitatively with a classification success rate of 100%. Most importantly, our chemosensor array has been fabricated by only mixing low cost commercially available reagents in situ, which means that complicated synthetic processes are avoided for Saccharide sensing. We believe this simple colorimetric assay that uses only commercially available reagents can create new, user-friendly supramolecular sensing pathways for Saccharides.
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A Saccharide Chemosensor Array Developed Based on an Indicator Displacement Assay Using a Combination of Commercially Available Reagents
Frontiers Media S.A., 2019Co-Authors: Yui Sasaki, Zhoujie Zhang, Tsuyoshi MinamiAbstract:Herein, a very simple colorimetric chemosensor array is reported for Saccharides (D-glucose, D-fructose, D-xylose, D-galactose, D-mannose, L-rhamnose, and N-acetyl-D-gluosamine). While various types of chemosensors for Saccharides have been investigated extensively to-this-date, tremendous additional efforts are still required on a regular basis for the syntheses of new chemosensors. Complicated syntheses would be a bottleneck, given that artificial receptor-based chemosensing systems are not so popular in comparison to biomaterial-based (e.g., enzyme-based) sensing systems. Toward this end, chemosensor array systems using molecular self-assembled materials can avoid the abovementioned synthetic efforts and achieve simultaneous qualitative and quantitative detection of a number of guest Saccharides. Using a practical approach, we focus on an indicator displacement assay (IDA) to fabricate a chemosensor array for colorimetric Saccharide sensing. On this basis, 3-nitrophenylboronic acid (3-NPBA) spontaneously reacts with catechol dyes such as alizarin red S (ARS), bromopyrogallol red (BPR), pyrogallol red (PR), and pyrocatechol violet (PV), and yields boronate ester derivatives with color changes. The addition of Saccharides into the aqueous solution of the boronate esters induces color recovery owing to the higher binding affinity of 3-NPBA for Saccharides, thus resulting in the release of dyes. By employing this system, we have succeeded in discriminating Saccharides qualitatively and quantitatively with a classification success rate of 100%. Most importantly, our chemosensor array has been fabricated by only mixing low cost commercially available reagents in situ, which means that complicated synthetic processes are avoided for Saccharide sensing. We believe this simple colorimetric assay that uses only commercially available reagents can create new, user-friendly supramolecular sensing pathways for Saccharides
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an extended gate type organic field effect transistor functionalised by phenylboronic acid for Saccharide detection in water
Chemical Communications, 2014Co-Authors: Tsuyoshi Minami, Tsukuru Minamiki, Yuki Hashima, Daisuke Yokoyama, Tomohito Sekine, Kenjiro Fukuda, Daisuke Kumaki, Shizuo TokitoAbstract:Saccharides in water are detected electrically using an extended-gate type organic field effect transistor (OFET) functionalised by a phenylboronic acid monolayer. The response patterns of the monoSaccharides are significantly different, suggesting that OFET devices can successfully read out the Saccharide recognition behaviour of boronic acids and be potentially applied to healthcare devices modified with supramolecular receptors.
Kenichi Kasai - One of the best experts on this subject based on the ideXlab platform.
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frontal affinity chromatography a unique research tool for biospecific interaction that promotes glycobiology
Proceedings of the Japan Academy. Series B Physical and biological sciences, 2014Co-Authors: Kenichi KasaiAbstract:Combination of bioaffinity and chromatography gave birth to affinity chromatography. A further combination with frontal analysis resulted in creation of frontal affinity chromatography (FAC). This new versatile research tool enabled detailed analysis of weak interactions that play essential roles in living systems, especially those between complex Saccharides and Saccharide-binding proteins. FAC now becomes the best method for the investigation of Saccharide-binding proteins (lectins) from viewpoints of sensitivity, accuracy, and efficiency, and is contributing greatly to the development of glycobiology. It opened a door leading to deeper understanding of the significance of Saccharide recognition in life. The theory is also concisely described.
Tomoyuki Nishimoto - One of the best experts on this subject based on the ideXlab platform.
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Three novel oligoSaccharides synthesized using Thermoanaerobacter brockii kojibiose phosphorylase
Chemistry Central Journal, 2007Co-Authors: Natsuko Takahashi, Tomoyuki Nishimoto, Eri Fukushi, Shuichi Onodera, Jun Kawabata, Noureddine Benkeblia, Norio ShiomiAbstract:Background Recently synthesized novel oligoSaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligoSaccharides using kojibiose phosphorylase. Results Three novel oligoSaccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to xylosylfructoside [ O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside] using Thermoanaerobacter brockii kojibiose phosphorylase. These oligoSaccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural characterisation. The ^1H and ^13C NMR signals of each Saccharide were assigned using 2D-NMR including COSY (correlated spectroscopy), HSQC (herteronuclear single quantum coherence), CH_2-selected E-HSQC (CH_2-selected Editing-HSQC), HSQC-TOCSY (HSQC-total correlation spectroscopy) and HMBC (heteronuclear multiple bond correlation). Conclusion The structure of three synthesized Saccharides were determined, and these oligoSaccharides have been identified as O -α-D-glucopyranosyl-(1→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 1 ), O -α-D-glucopyranosyl-(1→2)- O -α-D-glucopyranosyl-(1→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 2 ) and O -α-D-glucopyranosyl-(1→[2- O -α-D-glucopyranosyl-1]_2→2)- O -α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 3 ).
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three novel oligoSaccharides synthesized using thermoanaerobacter brockii kojibiose phosphorylase
Chemistry Central Journal, 2007Co-Authors: Natsuko Takahashi, Tomoyuki Nishimoto, Eri Fukushi, Shuichi Onodera, Jun Kawabata, Noureddine Benkeblia, Norio ShiomiAbstract:Recently synthesized novel oligoSaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligoSaccharides using kojibiose phosphorylase. Three novel oligoSaccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to xylosylfructoside [O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside] using Thermoanaerobacter brockii kojibiose phosphorylase. These oligoSaccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural characterisation. The 1H and 13C NMR signals of each Saccharide were assigned using 2D-NMR including COSY (correlated spectroscopy), HSQC (herteronuclear single quantum coherence), CH2-selected E-HSQC (CH2-selected Editing-HSQC), HSQC-TOCSY (HSQC-total correlation spectroscopy) and HMBC (heteronuclear multiple bond correlation). The structure of three synthesized Saccharides were determined, and these oligoSaccharides have been identified as O-α-D-glucopyranosyl-(1→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 1), O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl-(1→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 2) and O-α-D-glucopyranosyl-(1→[2-O-α-D-glucopyranosyl-1]2→2)-O-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (Saccharide 3).
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acceptor recognition of kojibiose phosphorylase from thermoanaerobacter brockii syntheses of glycosyl glycerol and myo inositol
Journal of Bioscience and Bioengineering, 2006Co-Authors: Takuo Yamamoto, Michio Kubota, Tomoyuki Nishimoto, Hajime Aga, Hikaru Watanabe, Hiroto Chaen, Shigeharu FukudaAbstract:The glucosyl transfer reaction of kojibiose phosphorylase (KP; EC 2.4.1.230) was examined using glycerol or myo-inositol as an acceptor. In the case of glycerol, KP produced two main transfer products: Saccharides A and B. The structure of Saccharide A was O-alpha-D-glucopyranosyl-(1-->1)-glycerol and that of Saccharide B was O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->1)-glycerol. These results show that KP transferred a glucose residue to the hydroxyl group at position 1 of glycerol. On the other hand, when myo-inositol was used as an acceptor, KP produced four transfer products: Saccharides 1-4. The structures of Saccharides 1 and 2 were O-alpha-D-glucopyranosyl-(1-->1)- and O-alpha-D-glucopyranosyl-(1-->5)-myo-inositol, respectively; those of Saccharides 3 and 4 were O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->1)- and O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->5)-myo-inositol, respectively. KP transferred a glucose residue to the hydroxyl group at position 1 or 5 of myo-inositol. On the basis of the structures of their glucosyl transfer products, glycerol and myo-inositol were found to have a common structure with three hydroxyl groups corresponding to the hydroxyl group of the glucose molecule at positions 2, 3 and 4. The conformation of these three hydroxyl groups in the structure is equatorial. This structure is the substrate recognition site of KP. It has been suggested that KP strictly recognizes the structures of glycerol and myo-inositol, and catalyzes the transfer reaction of a glucose residue to the hydroxyl group at position 1 in glycerol, and at position 1 or 5 in myo-inositol, corresponding to position 2 in glucose.
