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- Aldén, Anna, et al.
(författare)
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HPLC analysis of carbohydrate deficient transferrin isoforms isolated by the Axis-Shield %CDT method
- 2005
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Ingår i: Clinica Chimica Acta. - : Elsevier BV. - 0009-8981 .- 1873-3492. ; 356:1-2, s. 143-146
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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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| 6. |
- Bergström, Maria, et al.
(författare)
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Cholera toxin inhibitors studied with High-performance liquid affinity chromatography: arobust method to evaluate receptor-ligand interactions
- 2009
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Ingår i: Chemical Biology and Drug Design. - : Wiley. - 1747-0277 .- 1747-0285. ; 73:1, s. 132-141
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Tidskriftsartikel (refereegranskat)abstract
- Anti-adhesion drugs may be an alternative to antibiotics to control infection of micro-organisms. The well-characterized interaction between cholera toxin and the cellular glycolipid GM1 makes it an attractive model for inhibition studies in general. In this report, we demonstrate a high-performance liquid affinity chromatography approach called weak affinity chromatography to evaluate cholera toxin inhibitors. The cholera toxin B-subunit was covalently coupled to porous silica and a (weak) affinity column was produced. The K(D) values of galactose and meta-nitrophenyl alpha-d-galactoside were determined with weak affinity chromatography to be 52 and 1 mm, respectively, which agree well with IC(50) values previously reported. To increase inhibition potency multivalent inhibitors have been developed and the interaction with multivalent glycopolypeptides was also evaluated. The affinity of these compounds was found to correlate with the galactoside content but K(D) values were not obtained because of the inhomogeneous response and slow off-rate from multivalent interactions. Despite the limitations in obtaining direct K(D) values of the multivalent galactopolypeptides, weak affinity chromatography represents an additional and valuable tool in the evaluation of monovalent as well as multivalent cholera toxin inhibitors. It offers multiple advantages, such as a low sample consumption, high reproducibility and short analysis time, which are often not observed in other methods of analysis.
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| 7. |
- Bergström, Maria, et al.
(författare)
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Elucidating the selectivity of recombinant forms of Aleuria aurantia lectin using weak affinity chromatography
- 2012
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Ingår i: Journal of chromatography. B. - : Elsevier. - 1570-0232 .- 1873-376X. ; 885, s. 66-72
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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.
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| 8. |
- Bergström, Maria, et al.
(författare)
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Lectin affinity capillary electrophoresis in glycoform analysis applying the partial filling technique
- 2004
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 809:2, s. 323-329
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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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