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- Landberg, Eva, et al.
(author)
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Glycosylation of Bile-Salt-Stimulated Lipase from Human Milk : Comparison of Native and Recombinant Forms
- 1997
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In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 344:1, s. 94-102
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Journal article (peer-reviewed)abstract
- Bile-salt-stimulated lipase (BSSL) is an enzyme present in human milk. BSSL is important for fat digestion in infants. It contains one site for N-glycosylation and a serine/threonine-rich domain which is highly O-glycosylated. Both N- and O-linked sugar chains were studied on native BSSL from three donors and compared to the glycosylation of recombinant BSSL produced in Chinese hamster ovary or mouse fibroblast (C-127) cell lines. The carbohydrate composition of oligosaccharides was mapped using sugar and methylation analyses, enzyme-linked immunosorbant assay, and different separation techniques. Native BSSL was found to be highly glycosylated (19–26%). It contained a high amount of fucosylated oligosaccharides and expressed both Lewis a and Lewis b blood group antigens. None of the recombinant BSSL forms contained fucose. N-linked structures on native BSSL were identified as mainly mono- and disialylated biantennary complex type structures with or without fucose substitution. High-pH anion-exchange chromatography analysis indicated that the recombinant forms of BSSL contained similar types ofN-glycan structures differing mainly in their content of sialic acid and by the absence of fucose residues. Native BSSL contained predominantly large O-linked oligosaccharides. This was in contrast to the recombinant forms of BSSL which contained mainly short typeO-glycans with a high content of sialic acid. Interestingly, the estimated number of O-glycans attached to native BSSL was lower than that for the recombinant forms.
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| 2. |
- Landberg, Eva, et al.
(author)
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Temperature effects in high-performance anion-exchange chromatography of oligosaccharides
- 1998
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In: Journal of Chromatography A. - 0021-9673 .- 1873-3778. ; 814:1-2, s. 97-104
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Journal article (peer-reviewed)abstract
- High-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection has been widely used for analysis of mono-, oligo- and polysaccharides. Many factors that affect separation of carbohydrates by HPAEC have been evaluated, however effect of temperature has not been carefully studied. In the present study, neutral and sialylated oligosaccharides from human milk and different types of N-linked oligosaccharides were analysed by HPAEC at temperatures ranging from 13 to 30°C. N-Acetyl neuraminic acid, galacturonic acid and stachyose were also analysed since they have been used as internal standards when analysing various oligosaccharides by HPAEC. All oligosaccharides showed decreased retention times with increased temperature. Even small differences in temperature (i.e. ±5°) resulted in considerable changes in retention times. In addition, individual oligosaccharides showed different relative changes in retention time with increased temperature. By changing the temperature, a switch in elution order of individual oligosaccharides were sometimes found. These results show that retention times relative to an internal standard cannot be used for oligosaccharide identification unless temperature is carefully controlled. Regulation of temperature is also a valuable tool in achieving optimal separation of oligosaccharides by HPAEC.
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