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Acetylneuraminic Acid (acetylneuraminic + acid)
Selected AbstractsAn Expeditious Synthesis of N -Acetylneuraminic Acid ,- C -Glycosyl Derivatives (",- C -Glycosides") from the Anomeric AcetatesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2007Adeline Malapelle Abstract The reductive metallation of the readily available peracetylated derivatives of methyl N -acetylneuraminate 3a and 3b by samarium diiodide without any additive generates the corresponding anomeric samarium(III) organometallics. These intermediates react efficiently with carbonyl compounds under Barbier conditions, providing a fast synthesis of C -ketosides. The ,- and ,-acetates are equally effective, and excellent yields are obtained for coupling with cyclic ketones. The procedure has been conveniently applied to the synthesis of a C -ketoside of N -acetylneuraminic acid with an attached linker, ready to use as a building block in the elaboration of multivalent biological probes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] An Acyclic Aminonaphthyridine-Based Receptor for Carbohydrate Recognition: Binding Studies in Competitive SolventsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2007Monika Mazik Abstract 1H NMR spectroscopic and microcalorimetric titrations revealed that receptor 3b, consisting of three protonated 2-amino-1,8-naphthyridine units, binds N -acetylneuraminic acid (Neu5Ac), the most commonly occurring sialic acid, with high affinity in competitive solvents such as water/dimethyl sulfoxide. Receptor 3b is able to form neutral/charge-reinforced hydrogen bonds and ion pairs with Neu5Ac, similar to sialic acid-binding proteins. Furthermore, indications for weak binding of neutral sugars, such as methyl ,- D -glucopyranoside, D -maltose and D -cellobiose were provided by NMR spectroscopy. Molecular modelling calculations, synthesis and binding studies in aqueous media are described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] An Expeditious Synthesis of N -Acetylneuraminic Acid ,- C -Glycosyl Derivatives (",- C -Glycosides") from the Anomeric AcetatesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2007Adeline Malapelle Abstract The reductive metallation of the readily available peracetylated derivatives of methyl N -acetylneuraminate 3a and 3b by samarium diiodide without any additive generates the corresponding anomeric samarium(III) organometallics. These intermediates react efficiently with carbonyl compounds under Barbier conditions, providing a fast synthesis of C -ketosides. The ,- and ,-acetates are equally effective, and excellent yields are obtained for coupling with cyclic ketones. The procedure has been conveniently applied to the synthesis of a C -ketoside of N -acetylneuraminic acid with an attached linker, ready to use as a building block in the elaboration of multivalent biological probes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Development and validation of a ultra performance LC-ESI/MS method for analysis of metabolic phenotypes of healthy men in day and night urine samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 16-17 2008Xijun Wang Abstract Ultra-performance LC coupled to quadrupole TOF/MS (UPLC-QTOF/MS) in positive and negative ESI was developed and validated to analyze metabolite profiles for urine from healthy men during the day and at night. Data analysis using principal components analysis (PCA) revealed differences between metabolic phenotypes of urine in healthy men during the day and at night. Positive ions with mass-to-charge ratio (m/z) 310.24 (5.35 min), 286.24 (4.74 min) and 310.24 (5.63 min) were elevated in the urine from healthy men at night compared to that during the day. Negative ions elevated in day urine samples of healthy men included m/z 167.02 (0.66 min), 263.12 (2.55 min) and 191.03 (0.73 min), whilst ions m/z 212.01 (4.77 min) were at a lower concentration in urine of healthy men during the day compared to that at night. The ions m/z 212.01 (4.77 min), 191.03 (0.73 min) and 310.24 (5.35 min) preliminarily correspond to indoxyl sulfate, citric acid and N -acetylneuraminic acid, providing further support for an involvement of phenotypic difference in urine of healthy men in day and night samples, which may be associated with notably different activities of gut microbiota, velocity of tricarboxylic acid cycle and activity of sialic acid biosynthesis in healthy men as regulated by circadian rhythm of the mammalian bioclock. [source] NMR analysis of novel ganglioside GM4 analogues containing de- N -acetyl and lactamized sialic acid: probes for searching new ligand structures for human L-selectinMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2002Toshiyuki Hamada Abstract Detailed analysis of the 1H and 13C NMR spectra of two novel ganglioside GM4 analogues de- N -acetyl sialyl GM4 (1) and cyclic sialyl GM4 (2), which contain de- N -acetyl and lactamized sialic acid, respectively, instead of the usual N -acetylneuraminic acid, was carried out. The combination of NMR data, such as cyclization shifts, coupling pattern, intraresidual NOEs and the appearance of NH proton, provided the 5, 2B conformation for 2. Moreover, the conformation of a glycosidic bond connecting the Neu and Gal residues was determined by some interresidual NOEs in both 1 and 2. Copyright © 2002 John Wiley & Sons, Ltd. [source] Binding of the periodontitis associated bacterium Porphyromonas gingivalis to glycoproteins from human epithelial cellsMOLECULAR ORAL MICROBIOLOGY, Issue 5 2008U. Hallén Introduction:, In the present study we examined the ability of the periodontal pathogen Porphyromonas gingivalis to adhere to glycoconjugates on intact cells and to protein preparations of epithelial cells (KB cells). Methods:, The KB cell protein preparation was separated by sodium dodecyl sulfate,polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes by Western blotting. The membranes were used in overlay assays with labeled P. gingivalis. Flow cytometry was used to analyze attachment of bacteria to intact KB cells. Results:, Glycoconjugate expression on the KB cells and in the protein preparation was confirmed. Binding was detected to several bands on the Western blots. Flow cytometry showed a distinct increase in fluorescence for strain FDC 381. Preincubation of the bacteria with mannose, fucose, N -acetylglucosamine and N -acetylgalactosamine inhibited the binding to KB cells by approximately 30% whereas preincubation with N -acetylneuraminic acid reduced the binding by 60%. Conclusion:, These results indicate that carbohydrate structures are involved in the binding process of P. gingivalis to oral epithelial cells and that neuraminic acid plays a significant role in the adhesion process. [source] Removal of lipopolysaccharide and reactive oxygen species using sialic acid immobilized polysulfone dialyzerPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Jung-Jhih Chang Abstract Sialic acid (N -acetylneuraminic acid, NANA) was covalently immobilized onto the surface of a polysulfone (PSF) hollow fiber membrane. Prior to the immobilization, the surface of PSF was treated with ozone, followed by grafting with acrylic acid, and then the esterification of NANA. The surface concentration of NANA was determined by 2-thiobarbituric acid (TBA) test. Hemocompatibility, the capability of suppressing oxidative stress, and clearance of lipopolysaccharide (LPS) from the resulting hollow fiber membrane were evaluated. The results show that by immobilizing NANA onto PSF hollow fiber, the adhesion of platelet was reduced, while both APTT and PT were little affected. Furthermore, oxidative stress was suppressed by NANA-immobilized PSF hollow fibers. The level of LPS was also greatly reduced. Copyright © 2009 John Wiley & Sons, Ltd. [source] Analysis of inhibitor binding in influenza virus neuraminidasePROTEIN SCIENCE, Issue 4 2001Brian J. Smith Abstract 2,3-didehydro-2-deoxy- N -acetylneuraminic acid (DANA) is a transition state analog inhibitor of influenza virus neuraminidase (NA). Replacement of the hydroxyl at the C9 position in DANA and 4-amino-DANA with an amine group, with the intention of taking advantage of an increased electrostatic interaction with a conserved acidic group in the active site to improve inhibitor binding, significantly reduces the inhibitor activity of both compounds. The three-dimensional X-ray structure of the complexes of these ligands and NA was obtained to 1.4 Ĺ resolution and showed that both ligands bind isosterically to DANA. Analysis of the geometry of the ammonium at the C4 position indicates that Glu119 may be neutral when these ligands bind. A computational analysis of the binding energies indicates that the substitution is successful in increasing the energy of interaction; however, the gains that are made are not sufficient to overcome the energy that is required to desolvate that part of the ligand that comes in contact with the protein. [source] Consistent Bioactive Conformation of the Neu5Ac,(2,3)Gal Epitope Upon Lectin BindingCHEMBIOCHEM, Issue 18 2008Anirban Bhunia Dr. Get to NOE MAG: Partial structures of GQ1b,, the natural ligand of the myelin-associated glycoprotein (MAG), have been synthesized and subjected to NOE experiments to determine their bioactive conformations. The experiments show that the flexible ,(2,3)-glycosidic linkage between N -acetylneuraminic acid and galactose present in all ligands adopts a "sialyl Lewisx -type" binding mode. This information is valuable for the future design of conformationally preorganized MAG inhibitors. [source] | ||||||||||