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Sökning: LAR1:liu > Linnéuniversitetet > Ohlson Sten

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1.
  • Aldén, Anna, et al. (författare)
  • HPLC analysis of carbohydrate deficient transferrin isoforms isolated by the Axis-Shield %CDT method
  • 2005
  • Ingår i: Clinica Chimica Acta. - 0009-8981. ; 356:1-2, s. 143-146
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Carbohydrate-deficient transferrin (CDT) is elevated during prolonged overconsumption of alcohol and CDT is considered to be the most specific biochemical marker for alcohol overconsumption. However, an accurate method for analysing CDT is necessary because the test is frequently used for example in legal matters. Methods: Patient serum samples were analysed with the Axis-Shield %CDT and eluates were pooled together. Transferrin was purified from the pool by affinity chromatography and further analysed with HPLC to determine the ratios of different transferrin isoforms. Results: In the eluates using the Axis-Shield %CDT method, a substantial amount of trisialo transferrin was found, which is generally not considered a CDT isoform. Conclusions: The fact that trisialo transferrin is present may generate falsely elevated CDT results and it could at least partly explain the discrepancy between results of the Axis-Shield %CDT assay and HPLC in routine analysis. © 2005 Elsevier B.V. All rights reserved.
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2.
  • Bergström, Maria, et al. (författare)
  • Elucidating the selectivity of recombinant forms of Aleuria aurantia lectin using weak affinity chromatography
  • 2012
  • Ingår i: Journal of chromatography. B. - Elsevier. - 1570-0232. ; 885, s. 66-72
  • Tidskriftsartikel (refereegranskat)abstract
    • Aberrant glycosylation is connected to several pathological conditions and lectins are useful tools to characterize glycosylated biomarkers. The Aleuria aurantia lectin (AAL) is of special interest since it interacts with all types of fucosylated saccharides. AAL has been expressed in Escherichia coil as a fully functional recombinant protein. Engineered variants of AAL have been developed with the aim of creating monovalent lectins with more homogenous binding characteristics. Four different forms of AAL were studied in the present work: native AAL purified from A. aurantia mushrooms, recombinant AAL dimer, recombinant AAL monomer and recombinant AAL site 2 (S2-AAL). The affinities of these AAL forms toward a number of saccharides were determined with weak affinity chromatography (WAC). Disaccharides with fucose linked alpha 1-3 to GIcNAc interacted with higher affinity compared to fucose linked alpha 1-6 or alpha 1-4 and the obtained dissociation constants (K-d) were in the range of 10 mu M for all AAL forms. Tetra- and pentasaccharides with fucose in alpha 1-2, alpha 1-3 or alpha 1-4 had K-d values ranging from 0.1 to 7 mM while a large alpha 1-6 fucosylated oligosaccharide had a K-d of about 20 mu M. The recombinant multivalent AAL forms and native AAL exhibited similar affinities toward all saccharides, but S2-AAL had a lower affinity especially regarding a sialic acid containing fucosylated saccharide. It was demonstrated that WAC is a valuable technique in determining the detailed binding profile of the lectins. Specific advantages with WAC include a low consumption of non-labeled saccharides, possibility to analyze mixtures and a simple procedure using standard HPLC equipment.
3.
  • Bergström, Maria, et al. (författare)
  • Lectin Affinity Capillary Electrophoresis in Glycoform Analysis Applying the Partial Filling Technique
  • 2004
  • Ingår i: Journal of Chromatography B. ; 809, s. 323-329
  • Tidskriftsartikel (refereegranskat)abstract
    • The study of protein glycosylation and its significance in biological interactions is a field of growing interest. This work demonstrates a lectin-based separation of protein glycoforms of α1-acid glycoprotein (AGP or orosomucoid) with capillary electrophoresis. Glycoform analysis was performed with a "partial filling technique" with the lectin Concanavalin A (Con A) as affinity ligand. Con A separated human AGP into two peaks, the first peak included AGP glycoforms without biantennary glycans, and the second peak represented the fraction that had one or more biantennary glycans. The applicability of the method was demonstrated with the analysis of AGP from clinical samples and AGP treated with N-glycosidase F. The AGP separation was also used as a reporter system to estimate the dissociation constant (KD) between Con A and a competing sugar. © 2004 Elsevier B.V. All rights reserved.
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4.
  • Jungar, C, et al. (författare)
  • Analysis of carbohydrates using liquid chromatography-surface plasmon resonance immunosensing systems
  • 2000
  • Ingår i: Analytical Biochemistry. - 0003-2697. ; 281:2, s. 151-158
  • Tidskriftsartikel (refereegranskat)abstract
    • An immunosensing system based on surface plasmon resonance (SPR) was used for on-line detection and characterization of carbohydrate molecules separated by high-performance liquid chromatography. These analytes, with or without serum, were continuously separated and analyzed in the combined liquid chromatography-surface plasmon resonance (LC-SPR) system. By using weak and readily reversible monoclonal antibodies, the SPR system allowed specific on-line monitoring of the substances. To increase the specificity of the immunosensor, nonrelevant antibodies were used as reference in a serial flow cell. The sensitivity of the LC-SPR system was dependent on molecular weight of the carbohydrate, affinity of binding, and design of the sensor. (C) 2000 Academic Press.
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5.
  • Liljeblad, Mathias, et al. (författare)
  • A Lectin Immunosensor Technique for Determination of α1-Acid Glycoprotein Fucosylation
  • 2001
  • Ingår i: Analytical Biochemistry. - 0003-2697. ; 288:2, s. 216-224
  • Tidskriftsartikel (refereegranskat)abstract
    • The fucosylation of α1-acid glycoprotein (AGP), an acute-phase protein, is known to change in association with inflammatory diseases. Thus, fucosylation of AGP could be a potential diagnostic or prognostic marker. The change in fucosylation has previously been investigated using crossed affinoimmunoelectrophoresis, high-pH anion-exchange chromatography, and lectin ELISA. This study describes a surface plasmon resonance-based affinity biosensor assay for quantification of the fucosylation of AGP. Diluted EDTA plasma or serum was injected directly in a BIACORE 2000 biosensor. AGP was captured on the sensor surface using immobilized antibodies and a fucose-binding lectin from Aleuria aurentia was then used for the detection of fucosylation. The feature of the biosensor makes it possible to determine both the amount of bound AGP and the amount of bound lectin. Using a calibration curve it was possible to obtain a fucosylation ratio that was independent of AGP concentration. The assay was validated against a lectin ELISA and used to follow inflammation in patients with severe burns.
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6.
  • Liljeblad, M, et al. (författare)
  • Detection of low-molecular-weight heparin oligosaccharides (Fragmin™) using surface plasmon resonance
  • 1998
  • Ingår i: Journal of Molecular Recognition. - John Wiley and Sons. - 0952-3499. ; 11:1-6, s. 191-193
  • Tidskriftsartikel (refereegranskat)abstract
    • During the last decades there has been a growing realization of the central biological role that oligosaccharides and oligosaccharide–protein interactions play. One of the most striking examples is the use of heparin and low-molecular-weight heparin oligosaccharides (Fragmin™) to modify blood coagulation. Several monoclonal antibodies directed against glycosaminoglycan structures have been produced. However, their clinical use is limited by the difficulty of detection systems for oligosaccharides. In the present study we used a monoclonal antibody directed against heparin oligosaccharides prepared by partial nitrous acid deamination of heparin. Using a biosensor (BIAcore™), purified antibody was immobilized on sensor surfaces and binding of oligosaccharide was measured by surface plasmon resonance. Using this technique, it was possible to quantitate low-molecular-weight heparin oligosaccharides in nanomolar concentrations.
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7.
  • Mandenius, Carl-Fredrik, 1954-, et al. (författare)
  • Monitoring of influenza virus hemagglutinin in process samples using weak affinity ligands and surface plasmon resonance
  • 2008
  • Ingår i: Analytica Chimica Acta. - Elsevier. - 0003-2670. ; 623, s. 66-75
  • Tidskriftsartikel (refereegranskat)abstract
    • Surface plasmon resonance (SPR) was used to screen the interaction between a variety of affinity ligands and hemagglutinin (HA) from human influenza virus, with the aim of identifying low affinity ligands useful for the development of a rapid bioanalytical sensor. Three sialic acid-based structures and four lectins were evaluated as sensor ligands. The sialic acid-based ligands included a natural sialic acid-containing glycoprotein, human α1-acid glycoprotein (α1-AGP), and two synthetic 6′-sialyllactose-conjugates, with varying degree of substitution. The interaction of HA with the four lectin-based ligands, concanavalin A (Con A), wheat germ agglutinin (WGA), Maackia amurensis lectin (MAL), and Sambucus nigra agglutinin (SNA), showed a wide variation of affinity strengths. Affinity and kinetics data were estimated. Strong affinities were observed for Con A, WGA, α1-AGP, and a 6′-sialyllactose-conjugate with a high substitution degree, and low affinities were observed for MAL and a 6′-sialyllactose-conjugate with low substitution.The main objective, to identify a low affinity ligand which could be used for on-line monitoring and product quantification, was met by a 6′-sialyllactose–ovalbumin conjugate that had 0.6 mol ligand per mol carrier protein. The apparent affinity of this ligand was estimated to be 1.5 ± 0.03 μM (KD) on the SPR surface. Vaccine process samples containing HA were analyzed in the range 10–100 μg HA mL−1 and correlated with single-radial immunodiffusion. The coefficient of variation on the same chip was between 0.010 and 0.091.
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