Analysis of High-Molecular-Weight Oligosaccharides from Human Milk by Liquid Chromatography and MALDI-MS

1. The digestion of zinc present in human milk, cow's milk and a commercial babyfood was compared, using the piglet as a model for the human infant.2. In piglets given human milk the pH of stomach contents was approximately 1 and 0.4 units lower than that of animals given respectively cow's milk and babyfood. The pH values of intestinal contents were approximately neutral and did not vary with the type of feed.3. Hard casein curds were present throughout the stomachs and small intestines of animals fed on cow's milk or babyfood and between 55 and 70% Zn in these digesta samples were recovered in an insoluble form by centrifugation. In contrast, little solid material was observed in the digesta of animals fed on human milk, and 57 and 93% respectively of the Zn in digesta were recovered in a soluble form in the stomach and small intestine.4. Soluble fractions prepared by centrifugation of digesta were analysed by filtration on Sephadex G-150. After any of the three feeds, soluble Zn in stomach contents was mainly in a low-molecular-weight form. In intestinal samples, however, Zn was present in low- and high-molecular-weight forms. Whilst there were similar amounts of Zn in the low-molecular-weight form in all samples, approximately three times as much of the total intestinal Zn was in a soluble high-molecular-weight form complexed to proteins in the animals fed on human milk compared with those fed on cow's milk or babyfood.5. Analysis of protein-bound soluble Zn in intestinal samples on SDS-polyacrylamide gels resulted in a similar pattern of proteins for all feeds. Results indicated that at least some of these proteins were derived from intestinal secretions of the piglet.6. Some implications of these results in respect of the mode of digestion of Zn and its biological availability to the human infant are discussed.

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Semi-quantitative method for high molecular weight neuropeptides by high-performance liquid chromatography/thermospray mass spectrometry

Journal of Mass Spectrometry ◽

10.1002/bms.1200181009 ◽

1989 ◽

Vol 18 (10) ◽

pp. 897-903 ◽

Cited By ~ 11

Author(s):

Robert D. Voyksner ◽

Terry W. Pack

Keyword(s):

Mass Spectrometry ◽

Molecular Weight ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

High Molecular Weight ◽

High Performance ◽

Quantitative Method ◽

Thermospray Mass Spectrometry

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Molecular characterisation of high molecular weight glutenin allele Glu-B1h encoding 1Bx14+1By15 subunits in bread wheat (Triticum aestivum L.)

Crop and Pasture Science ◽

10.1071/cp13409 ◽

2014 ◽

Vol 65 (3) ◽

pp. 215 ◽

Cited By ~ 5

Author(s):

Lele Xiao ◽

Ke Wang ◽

Yanlin Liu ◽

Xingguo Ye ◽

Wujun Ma ◽

...

Keyword(s):

Mass Spectrometry ◽

Molecular Weight ◽

Liquid Chromatography ◽

High Molecular Weight ◽

Bread Wheat ◽

Sodium Dodecyl ◽

Reversed Phase ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Tof Ms

In this study, the authentic high molecular weight glutenin (HMW-GS) allele Glu-B1 h encoding for subunits 1Bx14 and 1By15 from German bread wheat cultivars Hanno and Imbros was identified and cross-verified by a suite of established protein analysis technologies, including sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reversed-phase high-performance liquid chromatography, reversed-phase ultra-performance liquid chromatography, and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). The complete encoding sequences were isolated by allele-specific PCR, and consist of 2367 bp for 1Bx14 and 2151 bp for 1By15 and encode 789 and 717 amino acid residues, respectively. The deduced molecular masses of two subunit genes were 82 340.13 Da and 74 736.13 Da, corresponding well to those determined by MALDI-TOF-MS. The presence and authenticity of 1Bx14 and 1By15 subunits were further confirmed by liquid chromatography coupled to tandem mass spectrometry and heterologous expression in E. coli. Comparative analysis demonstrated that 1Bx14 possessed one deletion and 20 single-nucleotide polymorphism variations compared with seven other Glu-B1 x-type HMW-GS genes that mainly resulted from C–T substitutions, whereas compared with five other Glu-B1 y-type HMW-GS genes, 1By15 displayed few variations. Phylogenetic analysis based on the complete coding sequences of the published HMW-GS genes showed that 1Bx14 had a high divergence with other 1Bx subunit genes, whereas 1By15 displayed greater similarity with 1By20. A possible evolutionary route for 1Bx14 gene formation is proposed, which might have resulted from an intra-strand illegitimate recombination event that occurred ~1.32 million years ago.

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