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Novel arabinan and galactan oligosaccharides from dicotyledonous plants.

Wefers D, Tyl CE, Bunzel M - Front Chem (2014)

Bottom Line: To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment.Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized.The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology Karlsruhe, Germany.

ABSTRACT
Arabinans and galactans are neutral pectic side chains and an important part of the cell walls of dicotyledonous plants. To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment. LC-MS(2) and one- and two-dimensional NMR spectroscopy were used for unambiguous structural characterization. It was demonstrated that arabinans contain β-(1→3)-linked arabinobiose as a side chain in quinoa seeds, while potato galactan was comprised of β-(1→4)-linked galactopyranoses which are interspersed with α-(1→4)-linked arabinopyranoses. Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized. The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

No MeSH data available.


CID MS2 mass spectrum of lithium cationized compound 2 (m/z 643).
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Figure 3: CID MS2 mass spectrum of lithium cationized compound 2 (m/z 643).

Mentions: Compound 2 was isolated by Bio-Gel P2 chromatography and semipreparative HPLC after Driselase digestion of pectic galactans from potato. A galactose/arabinose ratio of approximately 3:1 was determined by HPAEC monosaccharide analysis. Determination of the d/l monosaccharide configuration by GC-MS showed that arabinose was present in its l-configuration and galactose in its d-configuration. LC-PGC-MS resulted in a very broad peak with m/z 643 (corresponding to the lithium adduct of an oligosaccharide made up of three galactoses and one arabinose). The peak broadening is typical for sugars in their pyranose form on reversed phase columns. Besides the quasimolecular ion (m/z 643), the MS2 fragmentation pattern showed a high intensity of a 60 Da mass loss (m/z 583) and a water loss (m/z 625) (Figure 3). Hofmeister et al. (1991) investigated MS2 fragmentation patterns of lithium cationized hexopyranose disaccharides and described the mass losses observed here as characteristic for an (1→4)-linkage. The main fragment at m/z 481 represents the loss of anhydro-galactose. The absence of fragments representing the loss of an arabinose residue (mass losses of 132 Da or 150 Da) suggests that arabinose is not present in a terminal position. The fragments at m/z 463 and at m/z 421, which could represent 18 Da and 60 Da mass losses of m/z 481, may point to a (1→4)-linkage of the internal galactose. The intense fragment at m/z 349 may result from a 132 Da mass loss of m/z 481 or of a combined loss of galactose and arabinose. Although not all fragments can be explained, LC-MS2 points to an (1→4)-linked galactan containing an internal arabinose unit.


Novel arabinan and galactan oligosaccharides from dicotyledonous plants.

Wefers D, Tyl CE, Bunzel M - Front Chem (2014)

CID MS2 mass spectrum of lithium cationized compound 2 (m/z 643).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4226231&req=5

Figure 3: CID MS2 mass spectrum of lithium cationized compound 2 (m/z 643).
Mentions: Compound 2 was isolated by Bio-Gel P2 chromatography and semipreparative HPLC after Driselase digestion of pectic galactans from potato. A galactose/arabinose ratio of approximately 3:1 was determined by HPAEC monosaccharide analysis. Determination of the d/l monosaccharide configuration by GC-MS showed that arabinose was present in its l-configuration and galactose in its d-configuration. LC-PGC-MS resulted in a very broad peak with m/z 643 (corresponding to the lithium adduct of an oligosaccharide made up of three galactoses and one arabinose). The peak broadening is typical for sugars in their pyranose form on reversed phase columns. Besides the quasimolecular ion (m/z 643), the MS2 fragmentation pattern showed a high intensity of a 60 Da mass loss (m/z 583) and a water loss (m/z 625) (Figure 3). Hofmeister et al. (1991) investigated MS2 fragmentation patterns of lithium cationized hexopyranose disaccharides and described the mass losses observed here as characteristic for an (1→4)-linkage. The main fragment at m/z 481 represents the loss of anhydro-galactose. The absence of fragments representing the loss of an arabinose residue (mass losses of 132 Da or 150 Da) suggests that arabinose is not present in a terminal position. The fragments at m/z 463 and at m/z 421, which could represent 18 Da and 60 Da mass losses of m/z 481, may point to a (1→4)-linkage of the internal galactose. The intense fragment at m/z 349 may result from a 132 Da mass loss of m/z 481 or of a combined loss of galactose and arabinose. Although not all fragments can be explained, LC-MS2 points to an (1→4)-linked galactan containing an internal arabinose unit.

Bottom Line: To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment.Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized.The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology Karlsruhe, Germany.

ABSTRACT
Arabinans and galactans are neutral pectic side chains and an important part of the cell walls of dicotyledonous plants. To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment. LC-MS(2) and one- and two-dimensional NMR spectroscopy were used for unambiguous structural characterization. It was demonstrated that arabinans contain β-(1→3)-linked arabinobiose as a side chain in quinoa seeds, while potato galactan was comprised of β-(1→4)-linked galactopyranoses which are interspersed with α-(1→4)-linked arabinopyranoses. Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized. The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

No MeSH data available.