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High-performance Anion-exchange Chromatography (high-performance + anion-exchange_chromatography)
Selected AbstractsStereoselective Synthesis of myo -, neo -, L - chiro, D - chiro, allo -, scyllo -, and epi -Inositol Systems via Conduritols Prepared from p -BenzoquinoneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2003Michael Podeschwa Abstract A practical route is described for the flexible preparation of a wide variety of inositol stereoisomers and their polyphosphates. The potential of this approach is demonstrated by the synthesis of myo -, L - chiro -, D - chiro -, epi -, scyllo -, allo -, and neo -inositol systems. Optically pure compounds in either enantiomeric form can be prepared from p -benzoquinone via enzymatic resolution of a derived conduritol B key intermediate. High-performance anion-exchange chromatography with pulsed amperometric detection permits inositol stereoisomers to be resolved and detected with high sensitivity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Glycan profiling of urine, amniotic fluid and ascitic fluid from galactosialidosis patients reveals novel oligosaccharides with reducing end hexose and aldohexonic acid residuesFEBS JOURNAL, Issue 14 2010Cees Bruggink Urine, amniotic fluid and ascitic fluid samples of galactosialidosis patients were analyzed and structurally characterized for free oligosaccharides using capillary high-performance anion-exchange chromatography with pulsed amperometric detection and online mass spectrometry. In addition to the expected endo-,- N- acetylglucosaminidase-cleaved products of complex-type sialylated N -glycans, O -sulfated oligosaccharide moieties were detected. Moreover, novel carbohydrate moieties with reducing-end hexose residues were detected. On the basis of structural features such as a hexose,N -acetylhexosamine,hexose,hexose consensus sequence and di-sialic acid units, these oligosaccharides are thought to represent, at least in part, glycan moieties of glycosphingolipids. In addition, C1 -oxidized, aldohexonic acid-containing versions of most of these oligosaccharides were observed. These observations suggest an alternative catabolism of glycosphingolipids in galactosialidosis patients: oligosaccharide moieties from glycosphingolipids would be released by a hitherto unknown ceramide glycanase activity. The results show the potential and versatility of the analytical approach for structural characterization of oligosaccharides in various body fluids. [source] Isolation and structural characterization of an R-form lipopolysaccharide from Yersinia enterocolitica serotype O:8FEBS JOURNAL, Issue 3 2001Clemens Oertelt The lipopolysaccharide (LPS) of strain 8081-c-R2, a spontaneous R-mutant of Yersinia enterocolitica serotype O:8, was isolated using extraction with phenol/chloroform/light petroleum. Its compositional analysis indicated the presence of d -GlcN, d -Glc, lglycerodmanno - and dglycerodmanno -heptose, 3-deoxy- dmanno -oct-2-ulosonic acid (Kdo) and phosphate. From deacylated LPS obtained after successive treatment with hydrazine and potassium hydroxide, three oligosaccharides (1,3) were isolated using high-performance anion-exchange chromatography, the structures of which were determined by compositional analysis and one- and two-dimensional NMR spectroscopy as in which all sugars are pyranoses, and R and R, represent ,- d -Glc (in 1 and 2) and ,- d -GlcN (in 1 only), respectively. d -,- d -Hep is dglycero -,- dmanno -heptose, l -,- d -Hep is lglycero -,- dmanno- heptose, Kdo is 3-deoxy- dmanno -oct-2-ulosonic acid, and P is phosphate. The liberated lipid A was analyzed by compositional analyses and MALDI-TOF MS. Its ,- d -GlcN4P-(1,6)-,- d -GlcN-1,P backbone is mainly tetra-acylated with two amide- and one ester-linked (at O3 of the reducing GlcN) (R)-3-hydroxytetradecanoic acid residues, and one tetradecanoic acid that is attached to the 3-OH group of the amide-linked (R)-3-hydroxytetradecanoic acid of the nonreducing GlcN. Additionally, small amounts of tri- and hexa-acylated lipid A species occur. [source] Hydrothermal processing of rice husks: effects of severity on product distributionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2008Rodolfo Vegas Abstract BACKGROUND: Treatment in aqueous media (hydrothermal or autohydrolysis reactions) is an environmentally friendly technology for fractionating lignocellulosic materials. Rice husks were subjected to hydrothermal processing under a variety of operational conditions to cause the selective breakdown of xylan chains, in order to assess the effects of reaction severity on the distribution of reaction products. RESULTS: The effects of severity (measured by the severity factor, R0) on the concentrations of the major autohydrolysis products (monosaccharides, xylo- and glucooligosaccharides, xylooligosaccharide substituents, acetic acid, acid-soluble lignin and elemental nitrogen) were assessed. The interrelationship between the severity of treatment and molecular weight distribution was established by high-performance size-exclusion chromatography. Selected samples were subjected to refining treatments as ethyl acetate extraction and ion exchange for refining purposes, and the concentrates were assayed by high-performance anion-exchange chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CONCLUSIONS The protein equivalent of the products present in liquors accounted for 43 to 51% of the protein present in the raw rice husks. The concentrations of glucose (derived from starchy material) and arabinose (split from the xylan backbone) were fairly constant with severity. Even in treatments at low severity, high molecular weight compounds derived from xylan accounted for a limited part of the stoichiometric amount. Operating under harsh conditions, about 50% of the total xylan-derived compounds corresponded to fractions with a degree of polymerization (DP) < 9. After refining, saccharides accounted for more than 90% of the non-volatile components of the sample. The refined products showed a series of xylose oligomers up to about DP 13, and a series of acetylated xylose oligomers up to about DP 15. Copyright © 2008 Society of Chemical Industry [source] Highly automated and fast determination of raffinose family oligosaccharides in Lupinus seeds using pressurized liquid extraction and high-performance anion-exchange chromatography with pulsed amperometric detectionJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2008David Bansleben Abstract BACKGROUND: Taking into account several requirements for the determination of raffinose family oligosaccharides (RFOs) from Lupinus seeds,e.g., conducting plant breeding projects or food product development,a reasonable combination of efficient automated sample preparation and reliable analysis need to be developed and validated. RESULTS: In this regard pressurized liquid extraction was applied to extract the RFOs from ground and defatted lupin flour. Compared to many other publications, no further pretreatment, such as protein precipitation, was necessary to obtain satisfactory results applying ion chromatography with pulsed amperometric detection. The oligosaccharide content for the examined Lupinus albus samples were in the range 5.19,9.25 g kg,1 and for Lupinus angustifolius RFOs 3.49,4.75 g kg,1. Stachyose has always been the main component followed by raffinose and verbascose. CONCLUSION: The developed sample preparation and analytical method is suited to quantify raffinose, stachyose, verbascose and the disaccharide sucrose and, owing to a high degree of automation for sample preparation and relatively short analysis times by pretty peak separation, particularly high sample numbers can be accomplished. Copyright © 2008 Society of Chemical Industry [source] Isolation, structural features and rheological properties of water-extractable ,-glucans from different Greek barley cultivarsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2004Maria Irakli Abstract ,-Glucans were isolated from six Greek barley cultivars (Persefoni, Kos, Thessaloniki, Athinaida, Dimitra and Triptolemos) by water extraction at 47 °C, enzymatic removal of starch and protein and subsequent precipitation of the water-soluble ,-glucans with 37% (w/v) ammonium sulfate saturation. The purity of barley ,-glucans was high (>93% dry basis) with some small contamination by protein (<3.84%). The molecular size of the ,-glucan isolates was determined by high-performance size-exclusion chromatography (HPSEC); the weight-average molecular weights and the intrinsic viscosities ranged between 0.45 × 106 and 1.32 × 106 and 2.77 and 4.11 dl g,1, respectively. Structural features of barley ,-glucans were revealed by 13C NMR spectroscopy and high-performance anion-exchange chromatography (HPAEC) of the oligomers released by the hydrolytic action of lichenase. Lichenase degradation showed that ,-glucans from all barley cultivars consisted of blocks of cellotriosyl and cellotetraosyl units, accounting for 90.6,92.3% of the total oligomers released, with a molar proportion of these units between 2.31 and 2.77. Rheological measurements of aqueous solutions/dispersions of ,-glucans showed the behaviour of non-interacting polysaccharides and a transition from the typical viscoelastic response to gel-like properties after a time period that depended on the molecular size of the polysaccharide. The lowest molecular size ,-glucans from the Triptolemos cultivar showed shorter gelation times than their higher molecular weight counterparts. The effect of sugar incorporation (glucose, fructose, sucrose, xylose and ribose), at a concentration of 30% (w/v), to the ,-glucans gels (6% w/v) on compression parameters seemed to be related to the type of sugar used; the pentose sugars substantially reduced gel firming. Copyright © 2004 Society of Chemical Industry [source] Production and physicochemical characterization of resistant starch type III derived from pea starchMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 1 2003Undine Lehmann Abstract Smooth pea starch was used for the production of physiological important resistant starch type III. For reduction of the molecular weight of the starch, different strategies including enzymatic debranching and acid hydrolysis (lintnerization( were tested to obtain an optimal starting material for retrogradation. The resulting polymer chain lengths were analyzed by high-performance anion-exchange chromatography. Temperature regimes and starch concentrations in gel were optimized during the retrogradation with the aim to obtain a high yield of resistant starch. Optimal conditions led to resistant starch contents up to 74%. The products were thermostable and showed no loss of resistant structures after autoclaving. The peak temperatures of the thermal transition were at approximately 147°C. The resulting resistant starch products are suitable for the generation of functional foods. [source] O -Glycosylated 24,kDa human growth hormone has a mucin-like biantennary disialylated tetrasaccharide attached at Thr-60PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 13 2009Juan J. Bustamante Abstract MS was used to characterize the 24,kDa human growth hormone (hGH) glycoprotein isoform and determine the locus of O -linked oligosaccharide attachment, the oligosaccharide branching topology, and the monosaccharide sequence. MALDI-TOF/MS and ESI-MS/MS analyses of glycosylated 24,kDa hGH tryptic peptides showed that this hGH isoform is a product of the hGH normal gene. Analysis of the glycoprotein hydrolysate by high-performance anion-exchange chromatography with pulsed amperometric detection and HPLC with fluorescent detection for N -acetyl neuraminic acid (NeuAc) yielded the oligosaccharide composition (NeuAc2, N -acetyl galactosamine1, Gal1). After ,-elimination to release the oligosaccharide from glycosylated 24,kDa hGH, collision-induced dissociation of tryptic glycopeptide T6 indicated that there had been an O -linked oligosaccharide attached to Thr-60. The sequence and branching structure of the oligosaccharide were determined by ESI-MS/MS analysis of tryptic glycopeptide T6. The mucin-like O -oligosaccharide sequence linked to Thr-60 begins with N -acetyl galactosamine and branches in a bifurcated topology with one appendage consisting of galactose followed by NeuAc and the other consisting of a single NeuAc. The oligosaccharide moiety lies in the high-affinity binding site 1 structural epitope of hGH that interfaces with both the growth hormone and the prolactin receptors and is predicted to sterically affect receptor interactions and alter the biological actions of hGH. [source] Lipopolysaccharides from Serratia marcescens Possess One or Two 4-Amino-4-deoxy- L -arabinopyranose 1-Phosphate Residues in the Lipid A and D - glycero - D - talo -Oct-2-ulopyranosonic Acid in the Inner Core Region,CHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2006Evgeny Vinogradov Dr. Abstract The carbohydrate backbones of the core-lipid A region were characterized from the lipopolysaccharides (LPSs) of Serratia marcescens strains 111R (a rough mutant strain of serotype O29) and IFO 3735 (a smooth strain not serologically characterized but possessing the O-chain structure of serotype O19). The LPSs were degraded either by mild hydrazinolysis (de- O -acylation) and hot 4,M KOH (de- N -acylation), or by hydrolysis in 2,% aqueous acetic acid, or by deamination. Oligosaccharide phosphates were isolated by high-performance anion-exchange chromatography. Through the use of compositional analysis, electrospray ionization Fourier transform mass spectrometry, and 1H and 13C NMR spectroscopy applying various one- and two-dimensional experiments, we identified the structures of the carbohydrate backbones that contained D - glycero - D - talo -oct-2-ulopyranosonic acid and 4-amino-4-deoxy- L -arabinose 1-phosphate residues. We also identified some truncated structures for both strains. All sugars were D -configured pyranoses and ,-linked, except where stated otherwise. [source] | ||||||||||