Analysis of high-molecular-weight oligosaccharides from human milk by liquid chromatography and MALDI-MS

被引:76
作者
Finke, B [1 ]
Stahl, B
Pfenninger, A
Karas, M
Daniel, H
Sawatzki, G
机构
[1] Milupa GMBH & Co KG, Milupa Res, D-61381 Friedrichsdorf, Germany
[2] Univ Frankfurt, D-60590 Frankfurt, Germany
[3] Univ Giessen, Inst Ernahrungswissensch, D-35392 Giessen, Germany
关键词
D O I
10.1021/ac990094z
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
Pooled human milk oligosaccharides were fractionated by anion-exchange chromatography on AG 1-X2 and by an improved gel filtration procedure that allowed the separation of large oligosaccharides on Toyopearl HW 40 (S) and Bio-Gel P-6 columns, respectively. The analysis of the resulting nonderivatizated fractions by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) revealed several neutral and acidic high-molecular-weight oligosaccharides. So far unknown acidic oligosaccharides containing up to 20 monomers were detected ina molecular mass range of 2094-3626 Da. Furthermore, neutral structures containing up to 35 monosaccharides were identified after fractionation on Toyopearl HUT: 40 (S) and subsequent P-6 fractionation, demonstrating the suitability of the applied method for the preparation Of oligosaccharides in this high-molecular-mass range, The composition of the detected oligosaccharides was found to be the same as those previously identified in oligosaccharides of lower masses. However, an enormous structural heterogeneity was observed when acidic and neutral fractions were characterized by high-pH anion-exchange chromatography with pulsed amperometric!:detection (HPAEC-PAD), From our analysis we may conclude that each molecular mass identified by MALDI-EMS corresponds to a variety of isomeric structures. The total number of oligosaccharides occurring in human milk may consequently be much higher than estimated before.
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页码:3755 / 3762
页数:8
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