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  Subjects -> CHEMISTRY (Total: 795 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (553 journals)
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CHEMISTRY (553 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal   (Followers: 4)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31)
ACS Catalysis     Full-text available via subscription   (Followers: 25)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 13)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 8)
ACS Macro Letters     Full-text available via subscription   (Followers: 17)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 25)
ACS Nano     Full-text available via subscription   (Followers: 289)
ACS Photonics     Full-text available via subscription   (Followers: 5)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 8)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 6)
Acta Chromatographica     Full-text available via subscription   (Followers: 10)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 4)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 4)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 8)
Advanced Functional Materials     Hybrid Journal   (Followers: 35)
Advances in Chemical Engineering and Science     Open Access   (Followers: 23)
Advances in Chemical Science     Open Access   (Followers: 9)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 14)
Advances in Drug Research     Full-text available via subscription   (Followers: 16)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 12)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 15)
Advances in Nanoparticles     Open Access   (Followers: 12)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Polymer Science     Hybrid Journal   (Followers: 39)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 10)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 4)
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 4)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alchemy     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 4)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 29)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 181)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 18)
American Journal of Plant Physiology     Open Access   (Followers: 10)
American Mineralogist     Full-text available via subscription   (Followers: 3)
Analyst     Full-text available via subscription   (Followers: 35)
Angewandte Chemie     Hybrid Journal   (Followers: 17)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 232)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 1)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 12)
Anti-Infective Agents     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 12)
Applied Surface Science     Hybrid Journal   (Followers: 19)
Arabian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 4)
Autophagy     Full-text available via subscription   (Followers: 1)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 222)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 4)
Bioinspired Materials     Open Access  
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 17)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 5)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 30)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 24)
Bioorganic Chemistry     Hybrid Journal   (Followers: 5)
Biopolymers     Hybrid Journal   (Followers: 14)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 13)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 1)
Carbohydrate Research     Hybrid Journal   (Followers: 10)
Carbon     Hybrid Journal   (Followers: 54)
Catalysis for Sustainable Energy     Open Access   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 5)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 7)
Cellulose     Hybrid Journal   (Followers: 5)

        1 2 3 4 5 6 | Last

Journal Cover Carbohydrate Research
   [12 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
     Published by Elsevier Homepage  [2573 journals]   [SJR: 0.675]   [H-I: 77]
  • Facile enzymatic synthesis of sugar 1-phosphates as substrates for
           phosphorylases using anomeric kinases
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Yuan Liu , Mamoru Nishimoto , Motomitsu Kitaoka
      Three sugar 1-phosphates that are donor substrates for phosphorylases were produced at the gram scale from phosphoenolpyruvic acid and the corresponding sugars by the combined action of pyruvate kinase and the corresponding anomeric kinases in good yields. These sugar 1-phosphates were purified through two electrodialysis steps. α-d-Galactose 1-phosphate was finally isolated as crystals of dipotassium salts. α-d-Mannose 1-phosphate and 2-acetamido-2-deoxy-α-d-glucose 1-phosphate were isolated as crystals of bis(cyclohexylammonium) salts.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Hydroxypropyl cyclic β-(1→2)-d-glucans and epichlorohydrin
           β-cyclodextrin dimers as effective carbohydrate-solubilizers for
           polycyclic aromatic hydrocarbons
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Jae Min Choi , Daham Jeong , Jinglan Piao , Kyoungtea Kim , Andrew Bao Loc Nguyen , Nak-Jung Kwon , Mi-Kyung Lee , Im Soon Lee , Jae-Hyuk Yu , Seunho Jung
      The removal of polycyclic aromatic hydrocarbons by soil washing using water is extremely difficult due to their intrinsic hydrophobic nature. In this study, the effective aqueous solubility enhancements of seven polycyclic aromatic hydrocarbons by chemically modified hydroxypropyl rhizobial cyclic β-(1→2)-d-glucans and epichlorohydrin β-cyclodextrin dimer have been investigated for the first time. In the presence of hydroxypropyl cyclic β-(1→2)-d-glucans, the solubility of benzo[a]pyrene is increased up to 38 fold of its native solubility. The solubility of pyrene and phenanthrene dramatically increased up to 160 and 359. Coronene, chrysene, perylene, and fluoranthene also show an increase of 11, 23, 23, and 97 fold, respectively, of enhanced solubility by complexation with synthetic epichlorohydrin β-cyclodextrin dimer. The physicochemical properties of the complex are characterized by Fourier-transform infrared spectra and differential scanning calorimetry. Utilizing a scanning electron microscopy, the morphological structures of native benzo[a]pyrene, pyrene, phenanthrene, coronene, chrysene, perylene, fluoranthene and their complex with novel carbohydrate-solubilizers are studied. These results elucidate that polycyclic aromatic hydrocarbons are able to form an efficient complex with hydroxypropyl cyclic β-(1→2)-d-glucans and β-cyclodextrin dimer, suggesting the potential usage of chemically modified novel carbohydrate-solubilizers.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • A tree-step computational approach to simplify conformational
           determination of cellobiose and lactose
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Dong Chen , Zhichao Wei , Yuheng Yao , Bo Liu
      Great theoretical attentions have been paid on the conformational preference of individual molecular building blocks of carbohydrates because it is helpful for assignments of the experimental signals and explorations of the biological implications. A tree-step approach is applied here to simplify the conformational determination of phenyl β-cellobioside and benzyl β-lactoside, for which 35 and 23 initial structures are built, respectively. After the high-level calculations, low-energy conformers are determined and then compared with previous experimental and theoretical results. The low-energy conformers are reconstructed in our work for both cellobiose and lactose and the results show a quantitative agreement between the experimental signature and the predicted IR vibration assignment. In addition, two low-energy conformers, which are predicted in our work, have not been reported by the previous work using the traditional method. The tree-step computational approach provides an alternative timesaving and accurate method to focus on determining the preferred conformations of disaccharides.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Preparation of heparan sulfate-like polysaccharide and application in stem
           cell chondrogenic differentiation
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Shancheng Zhao , Zhen Wang , Jingxiao Chen , Jinghua Chen
      Heparan sulfate is a component of the extracellular matrix (ECM) that modulates individual development and cell growth through its interaction with growth factors. Structurally, heparan sulfate consists of repeating linear sulfated poly-anionic disaccharide structures. The K5 polysaccharide has the same structure as heparosan, and is the capsular polysaccharide of Escherichia coli K5 strain which serves as a precursor in heparin and heparan sulfate biosynthesis. Here, we prepared sulfated K5 polysaccharides that are structurally similar to heparan sulfate and investigated their biocompatibility and bioactivity in stem cell chondrogenic differentiation. Briefly, sulfation groups were added to –NH– and/or –OH of a precursor heparosan and the modified heparosan was qualitatively analyzed by FT-IR, 1H NMR, and 13C NMR techniques. Cell viability was not significantly affected by the sulfated K5 capsular polysaccharide. Relative mRNA expression of the chondrogenic differentiation marker COL2A1 was significantly upregulated in cells treated with the N,O-sulfated K5 polysaccharide confirming that the sulfated K5 capsular polysaccharide is able to stimulate chondrogenic differentiation. The main sulfation pattern for chondrogenic activity is N,6-O sulfation and the activity was not proportional to the sulfation level. This type of mimic was prepared in nearly a gram scale, supporting further structural study and 3 dimension stem cell culture. Together, the results of this study show that sulfated K5 capsular polysaccharides are able to stimulate chondrogenic differentiation without affecting cell viability.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Pectic polysaccharide from the green fruits of Momordica charantia
           (Karela): structural characterization and study of immunoenhancing and
           antioxidant properties
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Bibhash C. Panda , Soumitra Mondal , K. Sanjana P. Devi , Tapas K. Maiti , Somanjana Khatua , Krishnendu Acharya , Syed S. Islam
      A water soluble pectic polysaccharide (PS) isolated from the aqueous extract of the green fruits of Momordica charantia contains d-galactose and d-methyl galacturonate in a molar ratio of nearly 1:4. It showed splenocyte, thymocyte as well as macrophage activations. Moreover, it exhibited potent antioxidant activities. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and 1D and 2D NMR studies, the structure of the repeating unit of the pectic polysaccharide was established as:
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Supercritical water treatment for cello-oligosaccharide production from
           microcrystalline cellulose
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Lasse K. Tolonen , Minna Juvonen , Klaus Niemelä , Atte Mikkelson , Maija Tenkanen , Herbert Sixta
      Microcrystalline cellulose was treated in supercritical water at 380°C and at a pressure of 250bar for 0.2, 0.4, and 0.6s. The yield of the ambient-water-insoluble precipitate and its average molar mass decreased with an extended treatment time. The highest yield of 42wt% for DP2-9 cello-oligosaccharides was achieved after the 0.4s treatment. The reaction products included also 11wt% ambient-water-insoluble precipitate with a DPw of 16, and 6.1wt% monomeric sugars, and 37wt% unidentified degradation products. Oligo- and monosaccharide-derived dehydration and retro-aldol fragmentation products were analyzed via a combination of HPAEC-PAD–MS, ESI-MS/MS, and GC–MS techniques. The total amount of degradation products increased with treatment time, and fragmented (glucosyl n -erythrose, glucosyl n -glycolaldehyde), and dehydrated (glucosyl n -levoglucosan) were identified as the main oligomeric degradation products from the cello-oligosaccharides.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Enhancing the chemoenzymatic synthesis of arabinosylated
           xylo-oligosaccharides by GH51 α-l-arabinofuranosidase
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Faten Arab-Jaziri , Bastien Bissaro , Charles Tellier , Michel Dion , Régis Fauré , Michael J. O’Donohue
      Random mutagenesis was performed on the α-l-arabinofuranosidase of Thermobacillus xylanilyticus in order to enhance its ability to perform transarabinofuranosylation using natural xylo-oligosaccharides as acceptors. To achieve this goal, a two-step, high-throughput digital imaging protocol involving a colorimetric substrate was used to screen a library of 30,000 mutants. In the first step this screen selected for hydrolytically-impaired mutants, and in the second step the screen identified mutants whose global activity was improved in the presence of a xylo-oligosaccharide mixture. Thereby, 199 mutants displaying lowered hydrolytic activity and modified properties were detected. In the presence of these xylo-oligosaccharides, most of the 199 (i.e., 70%) enzymes were less inhibited and some (18) mutants displayed an unambiguous alleviation of inhibition (<25% loss of activity). More precise monitoring of reactions catalyzed by the most promising mutants revealed a significant improvement of the synthesis yields of transglycosylation products (up to 18% compared to 9% for the parental enzyme) when xylobiose was present in the reaction. Genetic analysis of improved mutants revealed that many of the amino acid substitutions that correlate with the modified phenotype are located in the vicinity of the active site, particularly in subsite −1. Consequently, we hypothesize that these mutations modify the active site topology or the molecular interaction network of the l-arabinofuranoside donor substrate, thus impairing the hydrolysis and concomitantly favoring transglycosylation onto natural acceptors.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Regioselectivity in the formation of di- and tri-6-O-mesitylenesulfonates
           of α-cyclodextrin
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Keisuke Yoshikiyo , Misaki Shinjo , Yoshihisa Matsui , Tatsuyuki Yamamoto
      The quantitative analysis of the reaction products for α-cyclodextrin (α-CD) with mesitylenesulfonyl chloride (MessCl) showed that di- and tri-mesitylenesulfonylation of the primary hydroxy groups of α-CD is regioselective. The reaction of mono-6-O-mesitylenesulfonyl-α-CD with MessCl in pyridine gave less 6A,6C-di-O-mesitylenesulfonyl-α-CD than 6A,6B-di-O-mesitylenesulfonyl-α-CD. The reaction of 6A,6D-di-O-mesitylenesulfonyl-α-CD with MessCl gave less 6A,6B,6E-tri-O-mesitylenesulfonyl-α-CD than 6A,6B,6D-tri-O-mesitylenesulfonyl-α-CD. These results indicate that the mesitylenesulfonyl group attached to glucopyranose-A (Glc-A) retards further mesitylenesulfonylation of the primary hydroxy group of Glc-C. The 1H NMR spectra of these modified α-CDs showed that the signal for the primary hydroxy and anomeric protons of Glc-C are significantly shifted upfield by the mesitylenesulfonyl group of Glc-A.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Chemical approach for the syntheses of GM4 isomers with sialic acid to
           non-natural linkage positions on galactose
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Kenta Kurimoto , Hatsuo Yamamura , Atsushi Miyagawa
      Cell-surface glycans containing sialic acid are involved in various biological phenomena. However, the syntheses of GM4 derivatives with (2→2) and (2→4) linkages have not been investigated to date. In this study, sialylation of all of the hydroxyl groups on galactose were investigated for the syntheses of GM4 isomers. Regioselective sialylation was achieved via protection of galactosyl acceptors using electron-rich benzyl groups. These synthetic sialylated glycans will prove to be useful tools for studying unidentified carbohydrate-mediated biological roles.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Force fields and scoring functions for carbohydrate simulation
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Xiuming Xiong , Zhaoqiang Chen , Benjamin P. Cossins , Zhijian Xu , Qiang Shao , Kai Ding , Weiliang Zhu , Jiye Shi
      Carbohydrate dynamics plays a vital role in many biological processes, but we are not currently able to probe this with experimental approaches. The highly flexible nature of carbohydrate structures differs in many aspects from other biomolecules, posing significant challenges for studies employing computational simulation. Over past decades, computational study of carbohydrates has been focused on the development of structure prediction methods, force field optimization, molecular dynamics simulation, and scoring functions for carbohydrate–protein interactions. Advances in carbohydrate force fields and scoring functions can be largely attributed to enhanced computational algorithms, application of quantum mechanics, and the increasing number of experimental structures determined by X-ray and NMR techniques. The conformational analysis of carbohydrates is challengeable and has gone into intensive study in elucidating the anomeric, the exo-anomeric, and the gauche effects. Here, we review the issues associated with carbohydrate force fields and scoring functions, which will have a broad application in the field of carbohydrate-based drug design.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Editorial board
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400




      PubDate: 2014-11-27T09:01:09Z
       
  • Graphical contents list
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400




      PubDate: 2014-11-27T09:01:09Z
       
  • Structure of the O-polysaccharide of Providencia alcalifaciens O2
           containing ascarylose and N-(l-alanyl)-d-glucosamine
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Olga G. Ovchinnikova , Magdalena Moryl , Alexander S. Shashkov , Alexander O. Chizhov , Nikolay P. Arbatsky , Anna M. Shpirt , Antoni Rozalski , Yuriy A. Knirel
      The O-polysaccharide was obtained by degradation of the lipopolysaccharide of Providencia alcalifaciens O2 under mild acidic conditions followed by GPC. The polysaccharide was found to contain two unusual components: 3,6-dideoxy-l-arabino-hexose (ascarylose, Asc) and 2-(l-alanyl)amino-2-deoxy-d-glucose (GlcNAla). Ascarylose was partially split off during lipopolysaccharide degradation and could be eliminated completely by selective acid hydrolysis, which also partially cleaved the β-GalNAc-(1→6) linkage. The following structure of the branched pentasaccharide repeating unit was established by 1H and 13C NMR spectroscopy of the O-polysaccharide and O-deacetylated polysaccharide, as well as products of partial acid hydrolysis:
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Chemoenzymatic synthesis of lacto-N-tetrasaccharide and sialyl
           lacto-N-tetrasaccharides
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Wenlong Yao , Jun Yan , Xi Chen , Fengshan Wang , Hongzhi Cao
      A concise and practical chemoenzymatic synthesis of lacto-N-tetraose, a major component and one of the most common core structures of human milk oligosaccharides (HMOs) was reported. This convergent synthesis relies on the glycosylation of a readily available lactoside acceptor with a lacto-N-biose donor generated from a highly efficient one-pot two-enzyme synthesis.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Synthesis of a heparin-related GlcN–IdoA sulfation-site variable
           disaccharide library and analysis by Raman and ROA spectroscopy
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Gavin J. Miller , Steen U. Hansen , Marek Baráth , Christian Johannessen , Ewan W. Blanch , Gordon C. Jayson , John M. Gardiner
      Synthesis of an array of differentially sulfated GlcN–IdoA disaccharides, accessible on good scale, directly from l-iduronate components is described. These are specifically directed to provide the sulfation variability at the key most common biologically relevant sulfation-variable l-IdoA O-2 and d-GlcN O-6 and amino sites of this heparin disaccharide. This sulfation-varied matrix has allowed the first evaluation of using Raman/ROA spectroscopy to characterize changes in spectra as a function of both site and level of sulfation with pure, defined heparin-related disaccharide species. This provides analysis of both similarities and differences to digest native heparin and this shows evidence of different types of changes in conformations and conformational freedom as a function of some specific sulfation changes at the disaccharide level. It is anticipated that this data set will open the way for applications to further site-specific sulfated saccharides and demonstrates the capability offered by Raman–ROA towards fingerprinting sulfation in heparin fragments.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Synthesis, characterization, and in vitro evaluation of
           artesunate-β-cyclodextrin conjugates as novel anti-cancer prodrugs
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Rui-jian Jiang , Yu-lin Zhao , Yun-jian Chen , Dan Xiao , Fen Wang , Bin Han , Jian Yang , Xia-li Liao , Li-Juan Yang , Chuan-zhu Gao , Bo Yang
      A novel series of artesunate-β-cyclodextrin (ATS-β-CD) conjugates, in which artesunate (ATS) was coupled covalently to one of the primary hydroxyl groups of β-cyclodextrin (β-CD) through amino bond formation, were synthesized and characterized by 1H NMR, HRMS, 2D NMR (ROESY), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the aqueous solubility of ATS-β-CD conjugates was 26–45 times better than that of free ATS. The cytotoxicity of the ATS-β-CD conjugates was evaluated on human colon cancer cell lines HCT116, LOVO, SW480, and HT-29, and the results indicated that ATS-2NβCD exhibited a very high cytotoxicity against HCT116, LOVO, and HT-29 with IC50 values of 0.58, 1.62, and 5.18μmol/L, respectively. In addition, the supposition of better cytotoxicity was further supported by the control experiment of fluorescent cyclodextrin.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Susceptibility of enoxaparin reducing end amino sugars to periodate
           oxidation
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Anna Alekseeva , Stefano Elli , Cesare Cosentino , Giangiacomo Torri , Annamaria Naggi
      There is a growing interest on glycol-split low-molecular weight heparins (gs-LMWHs), obtained by periodate oxidation of LMWHs, optionally followed by borohydride reduction, as potential anticancer and anti-inflammatory drugs. However, their structural characterization is still a challenging task, mainly because of the high microheterogeneity of the starting material. In addition, susceptibility to oxidation of some end-groups of LMWHs induces additional heterogeneity, making analysis of gs-LMWHs more complex. In our previous study we showed that 1,6-anhydro-d-mannosamine N-sulfate was affected by periodate, while its epimer 1,6-anhydro-d-glucosamine N-sulfate was resistant. In order to understand the apparently anomalous behavior of terminal 1,6-anhydro-d-mannosamine N-sulfate residues, in the present work we have studied by NMR spectroscopy and LC/MS the behavior of the reducing end amino sugar residues of the tetrasaccharides, isolated from the LMWH enoxaparin, in the presence of periodate. Their molecular mechanics conformational characterization has been also performed. We have shown that the C(2)–C(3) bond of the 1,6-anhydro-d-mannosamine residue can be split by periodate despite the N-substitution. Moreover, we have found that both terminal d-mannosamine N-sulfate and d-glucosamine N-sulfate, lacking the 1,6-anhydro-bridge, can be also oxidized by periodate but with a significantly lower rate. The present results suggest that the cis-e-/a-position of OH and NHSO3 − groups of N-sulfated 1,6-anhydro-d-mannosamine is not the only factor that makes these end residues susceptible to the oxidation. The 1,6-anhydro-bridge that ‘blocks’ the ring conformation appears another crucial factor for oxidation to occur. Moreover, we have shown that controlling the reaction time could permit to selectively split non-sulfated iduronic acids of enoxaparin chains without oxidizing terminal amino sugar residues, a finding that may be useful to obtain more structurally homogeneous gs-LMHWs.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Development of a 1H NMR structural-reporter-group concept for the analysis
           of prebiotic galacto-oligosaccharides of the
           [β-d-Galp-(1→x)]n-d-Glcp type
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Sander S. van Leeuwen , Bas J.H. Kuipers , Lubbert Dijkhuizen , Johannis P. Kamerling
      Some β-galactosidases (EC 3.2.1.23) are capable of producing mixtures of linear and branched galacto-oligosaccharides (GOS) with various types of glycosidic linkages [degree of polymerization (DP) 2–8; mainly Gal n Glc] when incubated under specific conditions with lactose. These products are generally applied in infant formula. However, for most galacto-oligosaccharide products only major components (low DP) or linkage patterns have been described. To build up a library of 1H and 13C NMR data, a detailed NMR study on commercially available GOS di- and trisaccharides, and some larger GOS oligosaccharides was carried out. Based on the fully assigned 1H and 13C chemical shifts of these model compounds, a 1H NMR structural-reporter-group concept was formulated to function as a tool in the structural analysis of single GOS components and GOS mixtures.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • 1H NMR analysis of the lactose/β-galactosidase-derived
           galacto-oligosaccharide components of Vivinal® GOS up to DP5
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Sander S. van Leeuwen , Bas J.H. Kuipers , Lubbert Dijkhuizen , Johannis P. Kamerling
      Vivinal® GOS is a galacto-oligosaccharide (GOS) product, prepared from lactose by incubation with Bacillus circulans β-galactosidase (EC 3.2.1.23). This complex mixture of saccharides with degree of polymerization (DP) between 1 and 8 is generally applied in infant nutrition. Here, a detailed structural description of the commercial product up to the DP5 level is given. First, Vivinal® GOS was subjected to DP analysis using HPLC-SEC (Rezex RSO-01 oligosaccharide Ag+ column) and 1H NMR analysis. Then, the product was fractionated on Bio-Gel P-2, and the obtained fractions were pooled according to DP, as indicated by MALDI-TOF-MS analysis. Finally, fractions of single DP, as well as their subfractions obtained by HPAEC-PAD on CarboPac PA-1, were analyzed by 1D/2D 1H/13C NMR spectroscopy and linkage analysis. In total, over 40 structures, providing a structural coverage of over 99% of the product, have been characterized. Detailed 1H and 13C NMR data, as well as G.U. values (glucose units; malto-oligosaccharide ladder) on CarboPac PA-1 of all oligosaccharides are included.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Biosynthesis of lactosylfructoside by an intracellular levansucrase from
           Bacillus methylotrophicus SK 21.002
    • Abstract: Publication date: Available online 22 November 2014
      Source:Carbohydrate Research
      Author(s): Chao Wu , Tao Zhang , Wanmeng Mu , Ming Miao , Bo Jiang
      Lactosylfructoside is a functional oligosaccharide consisting of D-glucose, D-galactose and D-fructose. In this work, lactosylfructoside was biosynthesized from sucrose as a fructosyl donor and lactose as an acceptor by an intracellular levansucrase derived from strain Bacillus methylotrophicus (B. methylotrophicus) SK21.002. The trisaccharide was purified from the product using a high performance liquid chromatography (HPLC) system and was confirmed to be lactosylfructoside by nuclear magnetic resonance (NMR) spectroscopy. The biosynthesis conditions (such as pH, temperature, enzyme dosage, substrate concentrations and the concentration ratio of the two substrates) for lactosylfructoside production were optimized. The optimum conditions for lactosylfructoside preparation were a pH of 6.5, temperature of 37 °C and enzyme dosage of 8 U/g substrates. The concentration of substrates (total lactose and sucrose) was 400 mg/mL, and the ratio of lactose to sucrose was 1:1. The optimum time for lactosylfructoside production was 20 h, the yield of lactosylfructoside under the optimal conditions was 143 mg/mL, and the lactosylfructoside conversion efficiency was 36%.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • α-Galactobiosyl Units: Thermodynamics and kinetics of their formation
           by transglcosylations catalyzed by the GH36 α-galactosidase from
           Thermotoga maritima
    • Abstract: Publication date: Available online 20 November 2014
      Source:Carbohydrate Research
      Author(s): Anna S. Borisova , Dina R. Ivanen , Kirill S. Bobrov , Elena V. Eneyskaya , Georgy Rychkov , Mats Sandgren , Anna A. Kulminskaya , Michael L. Sinnott , Konstantin A. Shabalin
      Broad regioselectivity of α-galactosidase from Thermotoga maritima (TmGal36A) is a limiting factor for application of the enzyme in the directed synthesis of galactooligosides. However, this property can be used as a convenient tool in studies of thermodynamics of a glycosidic bond. Here, a novel approach to energy difference estimation is suggested.Both transglycosylation and hydrolysis of three types of galactosidic linkages were investigated using total kinetics of formation and hydrolysis of pNP-galactobiosides catalyzed by monomeric glycoside hydrolase family 36 α-galactosidase from T. maritima, a retaining exo-acting glycoside hydrolase. We have estimated transition state free energy differences between the 1,2- and 1,3-linkage (ΔΔG‡ 0 values were equal 5.34±0.85 kJ/mol) and between 1,6-linkage and 1,3-linkage (ΔΔG‡ 0 = 1.46 ± 0.23 kJ/mol) in pNP-galactobiosides over the course of the reaction catalyzed by TmGal36A. Using the free energy difference for formation and hydrolysis of glycosidic linkages (ΔΔG ‡ F – ΔΔG‡ H ), we found that the 1,2-linkage was 2.93 ± 0.47 kJ/mol higher in free energy than the 1,3-linkage, and the 1,6-linkage 4.44±0.71 kJ/mol lower.
      Graphical abstract image Highlights

      PubDate: 2014-11-27T09:01:09Z
       
  • Editorial board
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399




      PubDate: 2014-11-27T09:01:09Z
       
  • Graphical contents list
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399




      PubDate: 2014-11-27T09:01:09Z
       
  • Efficient synthesis of ethisterone glycoconjugate via bis-triazole linkage
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Kunj B. Mishra , Bhuwan B. Mishra , Vinod K. Tiwari
      Synthesis of sugar based triazolyl azido-alcohols was accomplished via one pot click reaction of glycosyl alkynes with epichlorohydrin in aqueous medium. All the developed triazolyl azido-alcohols were further utilized for the synthesis of bis-triazolyl ethisterone glycoconjugates using CuAAC reaction. The developed triazole-linked ethisterone glycoconjugates would be crucial in androgen receptor pharmacology and chemical biology.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • myo-Inositol 1,3-acetals as early intermediates during the synthesis of
           cyclitol derivatives
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Bharat P. Gurale , Richa S. Sardessai , Mysore S. Shashidhar
      Synthetic sequences starting from commercially available myo-inositol necessarily involve protection–deprotection strategies of its six hydroxyl groups. Several strategies have been developed/attempted over the last several decades leading to the synthesis of naturally occurring phosphoinositols, their analogs, and cyclitol derivatives. Of late, myo-inositol 1,3-acetals, which can be obtained by the reductive cleavage of myo-inositol orthoesters have emerged as early intermediates for the synthesis of phosphorylated and other inositol derivatives. This mini-review is an attempt to illustrate the economy and convenience of using myo-inositol 1,3-acetals as early intermediates during syntheses from myo-inositol.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Concise synthesis of the tetrasaccharide repeating unit of the
           O-polysaccharide isolated from Edwardsiella tarda PCM 1156 strain
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Rituparna Das , Mukul Mahanti , Balaram Mukhopadhyay
      A convergent strategy has been developed for the synthesis of the tetrasaccharide repeating unit of the O-antigen from Edwardsiella tarda PCM 1156. Sequential glycosylations of a series of rationally protected monosaccharide intermediates were achieved either by the activation of thioglycosides using N-iodosuccinimide (NIS) in conjunction with H2SO4–silica or by activation of trichloroacetimidate by H2SO4–silica only. All glycosylation reactions resulted in the formation of the desired linkage with absolute stereoselectivity and yielded the required derivatives in good to excellent yields. Both azido and phthalimido groups have been used as the precursor of the desired acetamido group depending on the requirement of 1,2-cis- or 1,2-trans-glycosidic linkage.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Efficient synthesis of the tetrasaccharide repeating unit of the O-antigen
           of Escherichia coli O174 strain
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Ishani Bhaumik , Tamashree Ghosh , Anup Kumar Misra
      The tetrasaccharide repeating unit of the O-antigen of Escherichia coli O174 strain was synthesized applying sequential glycosylations of suitably functionalized monosaccharide intermediates. Activation of glycosyl trichloroacetimidate derivatives using nitrosyl tetrafluoroborate (NOBF4) has been used during the synthesis. The glycosylation steps were high yielding with satisfactory stereo outcome.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Design and synthesis of 4′-O-alkyl-chitobiosyl-4-methylumbelliferone
           as human chitinase fluorogenic substrates
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Boudewijn A. Duivenvoorden , Karen Ghauharali , Saskia Scheij , Rolf G. Boot , Johannes M.F.G. Aerts , Gijsbert A. van der Marel , Herman S. Overkleeft , Jeroen D.C. Codée
      The synthesis of three fluorogenic chitobiosyl derivatives, modified at the non-reducing 4′-OH with, either a methyl, an isopropyl or a cyclohexylmethyl substituent, is described. The 4′-capped 4-methylumbelliferyl chitobiosides are hydrolysed by the human chitinase CHIT1 following Michaelis–Menten kinetics and in contrast to unmodified chitobiosyl-4-methylumbelliferone do not undergo transglycosylation. The compounds are also relatively poor hexosaminidase substrates and thus provide useful alternatives to 4′-deoxychitobiosyl-4-methylumbelliferone, previously reported by us as fluorogenic substrate to monitor CHIT1 activity as a marker for Gaucher disease state.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Synthesis of C-xylopyranosyl- and xylopyranosylidene-spiro-heterocycles as
           potential inhibitors of glycogen phosphorylase
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): László Somsák , Éva Bokor , Beáta Czibere , Katalin Czifrák , Csenge Koppány , László Kulcsár , Sándor Kun , Enikő Szilágyi , Marietta Tóth , Tibor Docsa , Pál Gergely
      New derivatives of d-xylose with aglycons of the most efficient glucose derived inhibitors of glycogen phosphorylase were synthesized to explore the specificity of the enzyme towards the structure of the sugar part of the molecules. Thus, 2-(β-d-xylopyranosyl)benzimidazole and 3-substituted-5-(β-d-xylopyranosyl)-1,2,4-triazoles were obtained in multistep procedures from O-perbenzoylated β-d-xylopyranosyl cyanide. Cycloadditions of nitrile-oxides and O-peracetylated exo-xylal obtained from the corresponding β-d-xylopyranosyl cyanide furnished xylopyranosylidene-spiro-isoxazoline derivatives. Oxidative ring closure of O-peracetylated β-d-xylopyranosyl-thiohydroximates prepared from 1-thio-β-d-xylopyranose and nitrile-oxides gave xylopyranosylidene-spiro-oxathiazoles. The fully deprotected test compounds were assayed against rabbit muscle glycogen phosphorylase b to show moderate inhibition for 3-(2-naphthyl)-5-(β-d-xylopyranosyl)-1,2,4-triazole (IC50 =0.9mM) only.
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      PubDate: 2014-11-27T09:01:09Z
       
  • Glycosidic bond hydrolysis in septanosides: a comparison of mono-, di-,
           and 2-chloro-2-deoxy-septanosides
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Supriya Dey , N. Jayaraman
      A kinetic study of the hydrolytic stabilities of mono-, di-, and 2-chloro-2-deoxy septanosides, under acid-catalysis, is reported herein. A comparison of mono- and diseptanosides, shows that the glycosidic bond in the disaccharide is more stable than the monosaccharide. Further the glycosidic bond at the reducing end hydrolyzes almost twice as faster than that of the non-reducing end of the disaccharide. 2-Chloro-2-deoxy septanoside is found to be the most stable and its glycosidic bond hydrolysis occurs at elevated temperatures only. The orientation of the exo-cyclic hydroxymethyl group and the inductive effect are suggested to play a role in the rates of hydrolysis.
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      PubDate: 2014-11-27T09:01:09Z
       
  • Total synthesis of the bacillosamine containing α-l-serine linked
           trisaccharide of Neisseria meningitidis
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Madhu Emmadi , Suvarn S. Kulkarni
      Total synthesis of the bacillosamine containing l-serine linked O-trisaccharide of Neisseria meningitidis is described. The synthesis entails installation of two consecutive α-linkages including the coupling of bacillosamine with l-serine derivative.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Pyrenyl-imino-C2-glucosyl conjugate: synthesis, characterization, and
           ratiometric and reversible OFF–ON receptor for Hg2+
    • Abstract: Publication date: 18 November 2014
      Source:Carbohydrate Research, Volume 399
      Author(s): Sivaiah Areti , Vijaya Kumar Hinge , Chebrolu P. Rao
      A pyrenyl-imino-C2-glucosyl conjugate, L, has been synthesized and characterized. The L exhibits selective chromogenic as well as fluorescent property towards Hg2+ in a ratiometric manner by showing ∼30 fold enhanced fluorescence emission intensity. The fluorescence enhancement continues to be there even in the presence of thirteen other competitive metal ions studied. The sensing of Hg2+ is well demonstrated using various techniques, such as, fluorescence, absorption, visual color under UV light and ESI MS. A minimum detection limit of 18±2ppb was shown by L for Hg2+ in ethanol. All the experimental studies carried out supported the formation of 2:1 complex between L and Hg2+. The structure of the 2:1 complex was modeled at ab initio using HF and found a structure where Hg2+ is sandwiched between the two pyrenyl moieties. The reversibility and reusability of L has been demonstrated using fluoride ion.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Branching patterns in leaf starches from Arabidopsis mutants deficient in
           diverse starch synthases
    • Abstract: Publication date: Available online 15 November 2014
      Source:Carbohydrate Research
      Author(s): Fan Zhu , Eric Bertoft , Nicolas Szydlowski , Christophe d’Hulst , Koushik Seetharaman
      This is the first report on the cluster structure of transitory starch from Arabidopsis leaves. In addition to wild type, the molecular structures of leaf starch from mutants deficient in starch synthases (SS) including single enzyme mutants ss1-, ss2-, or ss3-, and also double mutants ss1- ss2- and ss1- ss3- were characterized. The mutations resulted in increased amylose content. Clusters from whole starch were isolated by partial hydrolysis using α-amylase of Bacillus amyloliquefaciens. The clusters were then further hydrolyzed with concentrated α-amylase of B. amyloliquefaciens to produce building blocks (α-limit dextrins). Structures of the clusters and their building blocks were characterized by chromatography of samples before and after debranching treatment. While the mutations increased the size of clusters, the reasons were different as reflected by the composition of their unit chains and building blocks. In general, all mutants contained more of a-chains that preferentially increased the number of small building blocks with only two chains. The clusters of the double mutant ss1-ss3- were very large and possessed also more of large building blocks with four or more chains. The results from transitory starch are compared with those from agriculturally important crops in the context that to what extent the Arabidopsis can be a true biotechnological reflection for starch modifications through genetic means.
      Graphical abstract image Highlights

      PubDate: 2014-11-27T09:01:09Z
       
  • Synthesis of unsymmetrical 3,6-branched Man5 oligosaccharide: a comparison
           between one-pot sequential glycosylation and stepwise synthesis
    • Abstract: Publication date: Available online 15 November 2014
      Source:Carbohydrate Research
      Author(s): Yan Zhang , Congcong Chen , Lan Jin , Haining Tan , Fengshan Wang , Hongzhi Cao
      An expeditious three-component, one-pot sequential glycosylation protocol has been developed for the preparation of 3,6-branched unsymmetrical mannopentaose (Man5), employing a mannose trisaccharide donor, a mannose monosaccharide donor and a mannose monosaccharide acceptor. The high efficiency of this one-pot procedure was demonstrated by comparison study with stepwise synthesis using the same three building blocks.
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      PubDate: 2014-11-27T09:01:09Z
       
  • The structure of the Morganella morganii lipopolysaccharide core region
           and identification of its genomic loci
    • Abstract: Publication date: Available online 13 November 2014
      Source:Carbohydrate Research
      Author(s): Evgeny Vinogradov , John H.E. Nash , Simon Foote , N. Martin Young
      The core region of the lipopolysaccharide of Morganella morganii serotype O:1ab was obtained by hydrolysis of the LPS and studied by 2D NMR, ESI MS, and chemical methods. Its structure was highly homologous to those from the two major members of the same Proteeaea tribe, Proteus mirabilis and Providencia alcalifaciens, and analysis of the M. morganii genome disclosed that the loci for its outer core, lipid A and Ara4N moieties are similarly conserved.
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      PubDate: 2014-11-27T09:01:09Z
       
  • Facile access to new C- glycosides and C- glycoside scaffolds
           incorporating functionalised aromatic moieties
    • Abstract: Publication date: Available online 11 November 2014
      Source:Carbohydrate Research
      Author(s): Philip Redpath , Kerry A. Ness , Joanne Rousseau , Simon J.F. Macdonald , Marie E. Migaud
      The tandem ene/intramolecular Sakurai cyclisation (IMSC) reaction has been successfully applied to the synthesis of a range of C-glycosides, with key intermediates offering opportunities for functionalization of the glycon moiety. To demonstrate the versatility of the approach to access the 2-deoxy-C-glycoside series, we synthesised diastereomerically pure C-glucoside and galactoside derivatives incorporating functionalised aromatic, heteroaromatic and bicyclic aromatic moieties, in addition to the C-homologue of (+/-)-β-2-deoxy-glucose 6-phosphate.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Araf51 with improved transglycosylation activities: One engineered
           biocatalyst for one specific acceptor
    • Abstract: Publication date: Available online 8 November 2014
      Source:Carbohydrate Research
      Author(s): Alizé Pennec , Richard Daniellou , Pascal Loyer , Caroline Nugier-Chauvin , Vincent Ferrières
      A random mutagenesis of the arabinofuranosyl hydrolase Araf51 has been run in order to access to efficient biocatalysts for the synthesis of alkyl arabinofuranosides. The mutants were selected on their ability to catalyze the transglycosylation reaction of p-nitrophenyl α-L-arabinofuranoside (pNP-Araf) used as a donor and various aliphatic alcohols as acceptors. This screening strategy underlined 5 interesting clones, each one corresponding to one acceptor. They appeared to be much more efficient in the transglycosylation reaction compared to the wild type enzyme whereas no self-condensation or hydrolysis products could be detected. Moreover, the high specificity of the mutants towards the alcohols for which they have been selected validates the screening process. Sequence analysis of the mutated enzymes revealed that, despite their location far from the active site, the mutations affect significantly the kinetics properties as well as the substrate affinity of these mutants towards the alcohol acceptors in the transglycosylation reaction.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Predict the glass transition temperature and plasticization of
           β-cyclodextrin/water binary system by molecular dynamics simulation
    • Abstract: Publication date: Available online 4 November 2014
      Source:Carbohydrate Research
      Author(s): Guohui Zhou , Jie Wan , Chengmei Liu , Wei Liu , Risi Wang
      The glass transition temperature, diffusion behavior and plasticization of β-cyclodextrin(β-CD), and three amorphous β-CD/water mixtures(3%, 5% and 10% [w/w] water, respectively) were investigated by molecular dynamics simulation, which were performed using Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies(COMPASS) force field and isothermal-isobaric ensembles. The specific volumes of four amorphous cells were obtained as a function of temperature. The glass transition temperatures(Tg) were estimated to be 334.25 K, 325.12 K, 317.32 K, and 305.41 K for amorphous β-CD containing 0%, 3%, 5% and 10% w/w water, respectively, which compares well with the values observed in published literature. The radial distribution function was computed to elucidate the intermolecular interactions between amorphous β-CD and water, which acts as a plasticizer. These results indicate that the hydrogen bond interactions of oxygen in hydroxyl ions was higher than oxygen in acetal groups in β-CD amorphous mixtures with that in water, due to less accessibility of ring oxygens to the surrounding water molecules. The mobility of water molecules was investigated over various temperature ranges, including the rubbery and glassy phases of the β-CD/water mixtures, by calculating the diffusion coefficients and the fractional free volume. In β-CD amorphous models, the higher mobility of water molecules was observed at temperatures above Tg, and almost no change was observed at temperatures below Tg.
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      PubDate: 2014-11-27T09:01:09Z
       
  • Structure of the O-specific polysaccharides from planktonic and biofilm
           cultures of Pseudomonas chlororaphis 449
    • Abstract: Publication date: Available online 31 October 2014
      Source:Carbohydrate Research
      Author(s): Evelina L. Zdorovenko , Alexander S. Shashkov , Marina V. Zhurina , Vladimir K. Plakunov , Yuriy A. Knirel
      O-specific polysaccharides were obtained from the lipopolysaccharides isolated from the planktonic and biofilm cultures of Pseudomonas chlororaphis 449 and studied by composition analysis and 1D and 2D 1H- and 13C-NMR spectroscopy. The following structure was established: where the degree of non-stoichiometric 6-O-acetylation of GalNAc is ∼60% in the planktonic form or ∼10% in biofilm.
      Graphical abstract image Highlights

      PubDate: 2014-11-27T09:01:09Z
       
  • Computational study to evaluate the birefringence of uniaxially oriented
           film of cellulose triacetate
    • Abstract: Publication date: Available online 31 October 2014
      Source:Carbohydrate Research
      Author(s): Daichi Hayakawa , Kazuyoshi Ueda
      The intrinsic birefringence of a cellulose triacetate (CTA) film is evaluated using the polarizability of the monomer model of the CTA repeating unit, which is calculated using the density functional theory (DFT). Since the CTA monomer is known to have three rotational isomers, referred to as gg, gt, and tg, the intrinsic birefringence of these isomers is evaluated separately. The calculation indicates that the monomer CTA with gg and gt structures shows a negative intrinsic birefringence, whereas the monomer unit with a tg structure shows a positive intrinsic birefringence. By using these values, a model of the uniaxially elongated CTA film is constructed with a molecular dynamics simulation, and the orientation birefringence of the film model was evaluated. The result indicates that the film has negative orientation birefringence and that its value is in good agreement with experimental results.
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      PubDate: 2014-11-27T09:01:09Z
       
  • Halogenated D-xylono-δ-lactams: Synthesis and Enzyme Inhibition study
    • Abstract: Publication date: Available online 31 October 2014
      Source:Carbohydrate Research
      Author(s): Naresh Bhuma , Madhuri Vangala , Roopa J. Nair , Sushma G. Sabharwal , Dilip D. Dhavale
      A concise synthesis of four C3 fluoro/chloroDxylonoδlactams 3/4 has been reported. The methodology involves CoreyLink approach with suitably protected 3oxoDglucofuranose to introduce F/Cl as well as ester/amide functionalities at C3 of glucose. In next steps, 5,6Oisopropylidene group was converted to the 5azido xylosugars that on opening of 1,2acetonide group, and intramolecular SchmidtBoyer reaction with TFA:H2O, in one pot, afforded lactams 3/4. Conformational aspect of δlactams was studied by the 1H NMR spectroscopy. The halogenated δlactams3/4 showed no inhibition against different glycosidase enzymes.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Structural characterization and gastroprotective property of a novel
           glucofructan from Allium ampeloprasum var. porrum
    • Abstract: Publication date: Available online 31 October 2014
      Source:Carbohydrate Research
      Author(s): Camila R.A. Malafaia , Bernadete P. da Silva , Luzineide W. Tinoco , José P. Parente
      A new polysaccharide with an estimated weight-average molar mass of 2.6 x 103 was isolated from Allium ampeloprasum var. porrum by hot water extraction, and purified by Sephacryl S-300 HR high-resolution chromatography. It was composed of D-fructose and D-glucose in 10 : 6 molar ratio, respectively. The structure of the glucofructan was investigated by chemical and spectroscopic methods, including methylation analysis, nuclear magnetic resonance and electrospray mass spectrometry (ES-MS). The results permitted the structure of the glucofructan to be written as α-D-Glcp-(1→1)-β-D-Fruf-(2→1)-{[α-D-Glcp-(1→6)-β-D-Fruf-(2→6)]-β-D-Fruf-(2→1)}4-β-D-Fruf-(2↔1)-α-D-Glcp. Results of the present study indicated that this new glucofructan exhibited significant gastroprotective property, using in vivo experimental models.
      Graphical abstract image

      PubDate: 2014-11-27T09:01:09Z
       
  • Graphical contents list
    • Abstract: Publication date: 29 October 2014
      Source:Carbohydrate Research, Volume 398




      PubDate: 2014-10-12T00:54:21Z
       
  • Editorial board
    • Abstract: Publication date: 29 October 2014
      Source:Carbohydrate Research, Volume 398




      PubDate: 2014-10-12T00:54:21Z
       
  • Database and data analysis application for structural characterization of
           gangliosides and sulfated glycosphingolipids by negative ion mass
           spectrometry
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Marko Rožman , Dragana Fabris , Tomislav Mrla , Željka Vukelić
      Gangliosides and sulfated glycosphingolipids, as building and functional components of animal cell membranes, participate in cell-to-cell interactions and signaling, but also in changes of cell architecture due to different pathophysiological events. In order to enable higher throughput and to facilitate structural characterization of gangliosides/sulfo-glycosphingolipids (GSL) and their neutral GSL counterparts by negative ion mass spectrometry (MS) and tandem MS techniques, a database and data analysis application have been developed. In silico developed glycosphingolipid database considers a high diversity of ceramide compositions, several sialic acid types (N-acetylneuraminic acid, N-glycolylneuraminic acid and 2-keto-3-deoxynononic acid) as well as possible additional substitutions/modifications of glycosphingolipids, such as O-acetylation, de-N-acetylation, fucosylation, glucuronosylation, sulfation, attachment of repeating terminal hexose–N-acetylhexosamine– (Hex–HexNAc–)1–6 extension, and possible lactone forms. Data analysis application, named GSL-finder, enables correlation of negative ion MS and/or low-energy tandem MS spectra with the database structures. The GSL-database construction and the GSL-finder application searching rules are explained. Validation conducted on GD1a fraction as well as on complex mixtures of native gangliosides isolated from different mammalian brain tissues (human fetal and adult brain, and calf brain tissue) demonstrated agreement with previous studies. Plain, fast, and automated routine for structural characterization of gangliosides/sulfated glycosphingolipids and their neutral GSL counterparts described here could facilitate and improve mass spectrometric analysis of complex glycosphingolipid mixtures originating from variety of normal and pathological biomaterial, where it is known that distinctive changes in glycosphingolipid composition occur.
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      PubDate: 2014-10-08T00:22:10Z
       
  • Synthesis of the tetrasaccharide repeating unit of the O-glycan from the
           polar flagellum flagellin of Azospirillum brasilense Sp7
    • Abstract: Publication date: 5 December 2014
      Source:Carbohydrate Research, Volume 400
      Author(s): Kumar Bhaskar Pal , Balaram Mukhopadhyay
      Chemical synthesis of the tetrasaccharide repeating unit of the O-glycan from the polar flagellum flagellin of Azospirillum brasilense Sp7 in the form of its p-methoxyphenyl glycoside is reported. The required glycosidic linkages have been accomplished by activation of thioglycosides with N-iodosuccinimide in the presence of H2SO4–silica. H2SO4–silica was found to be an effective alternative to the classical acid promoters like TfOH or TMSOTf and it can lead to the formation of both 1,2-cis and 1,2-trans glycosidic linkages depending on the protecting group manipulation and control of the reaction condition.
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      PubDate: 2014-10-08T00:22:10Z
       
  • A Synthesis of 6-Deoxy-6-Fluorosucrose Suitable For PET Applications
    • Abstract: Publication date: Available online 21 September 2014
      Source:Carbohydrate Research
      Author(s): Xuefeng Gao , Vikram Gaddam , Michael Harmata
      A new route to 6-deoxy-6-fluorosucrose has been developed. The process proceeds in 8 linear steps in 25% overall yield from sucrose. The steps incorporating fluorine and subsequent deprotection are quite rapid, making the procedure useful in the context of 18F-labelling for PET applications.
      Graphical abstract image

      PubDate: 2014-09-25T23:47:00Z
       
  • Preface
    • Abstract: Publication date: Available online 19 September 2014
      Source:Carbohydrate Research
      Author(s): N. Jayaraman



      PubDate: 2014-09-20T23:42:05Z
       
  • Structural determination of Streptococcus pneumoniae repeat units in
           serotype 41A and 41F capsular polysaccharides to probe gene functions in
           the corresponding capsular biosynthetic loci
    • Abstract: Publication date: Available online 16 September 2014
      Source:Carbohydrate Research
      Author(s): Bent O. Petersen , Ian C. Skovsted , Berit Smestad Paulsen , Antonio R. Redondo , Sebastian Meier
      We report the repeating unit structures of the native capsular polysaccharides of S. pneumoniae serotypes 41A and 41F. Structural determinations yielded six carbohydrate units in the doubly branched repeating unit to give the following structure for serotype 41A: The structure determinations were motivated (1) by an ambition to help close the remaining gaps in S. pneumoniae capsular polysaccharide structures, and (2) by the attempt to derive functional annotations of carbohydrate active enzymes in the biosynthesis of bacterial polysaccharides from the determined structures. An activity present in 41F but not 41A is identified as an acetyltransferase acting on the rhamnopyranosoyl sidechain E. The genes encoding the formation of the six glycosidic bonds in serogroup 41 were determined from the capsular polysaccharide structures of serotype 41A, 41F and genetically related serotypes, in conjunction with corresponding genomic information and computational homology searches. In combination with complementary information, NMR spectroscopy considerably simplifies the functional annotation of carbohydrate active enzymes in the biosynthesis of bacterial polysaccharides.
      Graphical abstract image Highlights

      PubDate: 2014-09-17T23:40:07Z
       
  • Some Findings in Transgalactosylations Employing Modified Donor Substrates
    • Abstract: Publication date: Available online 18 August 2014
      Source:Carbohydrate Research
      Author(s): Lars Kröger , Joachim Thiem
      The scope of transgalactosylation with β-galactosidase (bovine testis) was studied employing a series of modified donor substrates based on p-nitrophenyl β-D-galactopyranoside and as uniform acceptor allyl 2-N-acetamido-2-deoxy-α-D-galactopyranoside. Structurally diverse donor molecules were recognized by the enzyme and led to novel disaccharide components, yet an excessive structural distortion was not accepted.
      Graphical abstract image

      PubDate: 2014-08-18T21:00:02Z
       
 
 
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