The Experts below are selected from a list of 70668 Experts worldwide ranked by ideXlab platform
Tadashi Araki - One of the best experts on this subject based on the ideXlab platform.
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chemo Enzymatic synthesis of 2 3 dideoxy 3 fluoro β d guanosine via 2 3 dideoxy 3 fluoro α d ribose 1 phosphate
Tetrahedron Letters, 2003Co-Authors: Hironori Komatsu, Tadashi ArakiAbstract:Abstract 2,3-Dideoxy-3-fluoro-α- d -ribose 1-phosphate 2 was stereoselectively synthesized and converted to 2′,3′-dideoxy-3-fluoro-β- d -guanosine 1 by Enzymatic Reaction using purine nucleoside phosphorylase. This chemo-Enzymatic strategy was first applied to the synthesis of 1 .
Hironori Komatsu - One of the best experts on this subject based on the ideXlab platform.
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chemo Enzymatic synthesis of 2 3 dideoxy 3 fluoro β d guanosine via 2 3 dideoxy 3 fluoro α d ribose 1 phosphate
Tetrahedron Letters, 2003Co-Authors: Hironori Komatsu, Tadashi ArakiAbstract:Abstract 2,3-Dideoxy-3-fluoro-α- d -ribose 1-phosphate 2 was stereoselectively synthesized and converted to 2′,3′-dideoxy-3-fluoro-β- d -guanosine 1 by Enzymatic Reaction using purine nucleoside phosphorylase. This chemo-Enzymatic strategy was first applied to the synthesis of 1 .
Yoshiki Chujo - One of the best experts on this subject based on the ideXlab platform.
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heavy metal free 19f nmr probes for quantitative measurements of glutathione reductase activity using silica nanoparticles as a signal quencher
Bioorganic & Medicinal Chemistry, 2012Co-Authors: Kazuo Tanaka, Narufumi Kitamura, Yoshiki ChujoAbstract:Abstract For the quantitative assessment of the glutathione reductase (GR) activity with a 19 F NMR spectroscopy, we developed the heavy metal-free probes based on silica nanoparticles modified with water-soluble perfluorinated dendrimers via the disulfide linkers. Before Enzymatic Reaction, the molecular rotation of the perfluorinated dendrimers is highly restricted, and the magnitude of 19 F NMR signals from the perfluorinated dendrimers can be suppressed. By the reductive cleavage of the disulfide linkers with the reduced glutathione-mediated Enzymatic Reaction of GR, perfluorinated dendrimers can be released from the surfaces of the nanoparticles. Consequently, the 19 F NMR signals of perfluorinated dendrimers were recovered. The Enzymatic activity of GR was determined from the increase of the magnitude of 19 F NMR signals. Finally, to demonstrate the feasibility of the probe in the presence of miscellaneous molecules under bio-mimetic conditions, the comparison study was executed with the cancer cell lysate. The value determined from our method showed a good agreement with that from the conventional method.
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bimodal quantitative monitoring for Enzymatic activity with simultaneous signal increases in 19f nmr and fluorescence using silica nanoparticle based molecular probes
Bioconjugate Chemistry, 2011Co-Authors: Kazuo Tanaka, Narufumi Kitamura, Yoshiki ChujoAbstract:We describe the bimodal quantitative assay for Enzymatic activity in 19F NMR spectroscopy and fluorescence spectroscopy using a nanoparticle-based molecular probe. Perfluorinated dendrimers were tethered on silica nanoparticles with a phosphate-caged fluorescein as a linker. Before Enzymatic Reaction, the molecular rotation of the perfluorinated dendrimers should be highly restricted, and the 19F NMR signals from the perfluorinated dendrimers were too broad to be detected relative to the noise level. Fluorescence signals of fluorescein were suppressed by the presence of the diphosphate groups. Following the Enzymatic Reaction with an alkaline phosphatase, perfluorinated dendrimers and fluorescein were released, and the NMR signals of perfluorinated dendrimers and strong fluorescence from fluorescein were correspondingly observed. The Enzymatic activity and Reaction rates of the hydrolysis of alkaline phosphatase were detected from the increases of fluorescence and 19F NMR signals. Finally, the feasibility...
Yunsheng Xia - One of the best experts on this subject based on the ideXlab platform.
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Enzymatic Reaction modulated gold nanorod end to end self assembly for ultrahigh sensitively colorimetric sensing of cholinesterase and organophosphate pesticides in human blood
Analytical Chemistry, 2015Co-Authors: Yunsheng XiaAbstract:We present herein the first reported self-assembly modulation of gold nanorods (AuNRs) by Enzymatic Reaction, which is further employed for colorimetric assays of cholinesterase (ChE) and organophosphate pesticides (OPs) in human blood. ChE catalyzes its substrate (acetylthiocholine) and produces thiocholine and acetate acid. The resulting thiols then react with the tips of the AuNRs by S–Au conjunction and prevent subsequent cysteine-induced AuNR end-to-end (EE) self-assembly. Correspondingly, the AuNR surface plasmon resonance is regulated, which results in a distinctly ratiometric signal output. Under optimal conditions, the linear range is 0.042 to 8.4 μU/mL, and the detection limit is as low as 0.018 μU/mL. As ChE is incubated with OPs, the Enzymatic activity is inhibited. So, the cysteine-induced assembly is observed again. On the basis of this principle, OPs can be well determined ranging from 0.12 to 40 pM with a 0.039 pM detection limit. To our knowledge, the present quasi pU/mL level sensitivity...
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Enzymatic Reaction Modulated Gold Nanorod End-to-End Self-Assembly for Ultrahigh Sensitively Colorimetric Sensing of Cholinesterase and Organophosphate Pesticides in Human Blood
2015Co-Authors: Yunsheng XiaAbstract:We present herein the first reported self-assembly modulation of gold nanorods (AuNRs) by Enzymatic Reaction, which is further employed for colorimetric assays of cholinesterase (ChE) and organophosphate pesticides (OPs) in human blood. ChE catalyzes its substrate (acetylthiocholine) and produces thiocholine and acetate acid. The resulting thiols then react with the tips of the AuNRs by S–Au conjunction and prevent subsequent cysteine-induced AuNR end-to-end (EE) self-assembly. Correspondingly, the AuNR surface plasmon resonance is regulated, which results in a distinctly ratiometric signal output. Under optimal conditions, the linear range is 0.042 to 8.4 μU/mL, and the detection limit is as low as 0.018 μU/mL. As ChE is incubated with OPs, the Enzymatic activity is inhibited. So, the cysteine-induced assembly is observed again. On the basis of this principle, OPs can be well determined ranging from 0.12 to 40 pM with a 0.039 pM detection limit. To our knowledge, the present quasi pU/mL level sensitivity for ChE and the quasi femtomolar level sensitivity for OPs are at least 500 and 7000 times lower than those of previous colorimetric methods, respectively. The ultrahigh sensitivity results from (1) the rational choice of anisotropic AuNRs as building blocks and reporters and (2) the specific structure of the Enzymatic thiocholine. Because of ultrahigh sensitivity, serum samples are allowed to be extremely diluted in the assay. Accordingly, various nonspecific interactions, even from glutathione/cysteine, are well avoided. So, both ChE and OPs in human blood can be directly assayed without any prepurification, indicating the simplicity and practical promise of the proposed method
Wilhelm T S Huck - One of the best experts on this subject based on the ideXlab platform.
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molecular engineering of robustness and resilience in Enzymatic Reaction networks
Journal of the American Chemical Society, 2017Co-Authors: Albert S Y Wong, Aleksandr A Pogodaev, Ilia N Vialshin, Britta Helwig, Wilhelm T S HuckAbstract:Living systems rely on complex networks of chemical Reactions to control the concentrations of molecules in space and time. Despite the enormous complexity in biological networks, it is possible to identify network motifs that lead to functional outputs such as bistability or oscillations. One of the greatest challenges in chemistry is the creation of such functionality from chemical Reactions. A key limitation is our lack of understanding of how molecular structure impacts on the dynamics of chemical Reaction networks, preventing the design of networks that are robust (i.e., function in a large parameter space) and resilient (i.e., reach their out-of-equilibrium function rapidly). Here we demonstrate that Reaction rates of individual Reactions in the network can control the dynamics by which the system reaches limit cycle oscillations, thereby gaining information on the key parameters that govern the dynamics of these networks. We envision that these principles will be incorporated into the design of net...
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preprogramming complex hydrogel responses using Enzymatic Reaction networks
Angewandte Chemie, 2017Co-Authors: Sjoerd G J Postma, Ilia N Vialshin, Casper Y Gerritsen, Min Bao, Wilhelm T S HuckAbstract:The creation of adaptive matter is heavily inspired by biological systems. However, it remains challenging to design complex material responses that are governed by Reaction networks, which lie at the heart of cellular complexity. The main reason for this slow progress is the lack of a general strategy to integrate Reaction networks with materials. Herein we use a systematic approach to preprogram the response of a hydrogel to a trigger, in this case the enzyme trypsin, which activates a Reaction network embedded within the hydrogel. A full characterization of all the kinetic rate constants in the system enabled the construction of a computational model, which predicted different hydrogel responses depending on the input concentration of the trigger. The results of the simulation are in good agreement with experimental findings. Our methodology can be used to design new, adaptive materials of which the properties are governed by Reaction networks of arbitrary complexity.
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a compartmentalized out of equilibrium Enzymatic Reaction network for sustained autonomous movement
ACS central science, 2016Co-Authors: Marlies Nijemeisland, Loai K. E. A. Abdelmohsen, Wilhelm T S Huck, Daniela A WilsonAbstract:Every living cell is a compartmentalized out-of-equilibrium system exquisitely able to convert chemical energy into function. In order to maintain homeostasis, the flux of metabolites is tightly controlled by regulatory Enzymatic networks. A crucial prerequisite for the development of lifelike materials is the construction of synthetic systems with compartmentalized Reaction networks that maintain out-of-equilibrium function. Here, we aim for autonomous movement as an example of the conversion of feedstock molecules into function. The flux of the conversion is regulated by a rationally designed Enzymatic Reaction network with multiple feedforward loops. By compartmentalizing the network into bowl-shaped nanocapsules the output of the network is harvested as kinetic energy. The entire system shows sustained and tunable microscopic motion resulting from the conversion of multiple external substrates. The successful compartmentalization of an out-of-equilibrium Reaction network is a major first step in harne...
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rational design of functional and tunable oscillating Enzymatic networks
Nature Chemistry, 2015Co-Authors: Sergey Semenov, Albert S Y Wong, Van Der R M Made, Sgj Postma, Joost Groen, Van Hwh Rik Roekel, De Tfa Tom Greef, Wilhelm T S HuckAbstract:In vitro assembly of out-of-equilibrium Enzymatic Reaction networks has proved challenging, limiting the development of autonomous synthetic systems. Now, a methodology has been developed to construct an Enzymatic Reaction network producing oscillations of active trypsin. The modular approach allows amplification or analog-to-digital conversion of the oscillations, and control over a self-assembly process.
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threshold sensing through a synthetic Enzymatic Reaction diffusion network
Angewandte Chemie, 2014Co-Authors: Sergey Semenov, De Tfa Tom Greef, Albert J Markvoort, Wilhelm T S HuckAbstract:A wet stamping method to precisely control concentrations of enzymes and inhibitors in place and time inside layered gels is reported. By combining Enzymatic Reactions such as autocatalysis and inhibition with spatial delivery of components through soft lithographic techniques, a biochemical Reaction network capable of recognizing the spatial distribution of an enzyme was constructed. The experimental method can be used to assess fundamental principles of spatiotemporal order formation in chemical Reaction networks.