Polysaccharides of the Red Alga Rhodymenia pertusa Part II. Cell-Wall Glucan; Proton Magnetic Resonance Studies on Permethylated Polysaccharides

Abstract

The cell-wall polysaccharide from R. pertusa has been shown, by g.l.c, mass spectrum, and p.m.r. studies on the methylated derivative, to consist of β-(1 → 4)-linked-D-glucopyranose residues. The assessment of anomeric configuration in polysaccharides by p.m.r. spectroscopy is illustrated by the spectra of methylated amylose and cellulose. The preparation of anilides for mass spectral analysis of sugars is suggested.

Structure of a Hemicellulose A Fraction in Dietary Fiber from the Seed of Grape Variety Palomino (Vitis vinifera cv. Palomino)

“…Methylation of HA-1 produced a pale-yellow solid product with a specific rotation of [α] 25 D −52.9° ( c 1.34, chloroform), indicative of the existence of β- d -glycosidic linkages. This was confirmed by the NMR spectroscopic data (δ 4.25 for H-1 and δ 102.5 for C-1). , A portion of the methylated polysaccharide was hydrolyzed, and the resulting sugars were converted into their corresponding partially methylated alditol acetates and analyzed by GC and GC−MS . The results obtained are summarized in Table .…”

“…This was confirmed by the NMR spectroscopic data (δ 4.25 for H-1 and δ 102.5 for C-1). 18,19 A portion of the methylated polysaccharide was hydrolyzed, and the resulting sugars were converted into their corresponding partially methylated alditol acetates and analyzed by GC 20 and GC-MS. 21 The results obtained are summarized in Table 1.…”

“…The smallest of the acidic oligosaccharides (AOS-1) is an aldobiouronic acid having an [R] 25 D +102.0°, indicative of the existence of an R-D-glycosidic link; this was confimed by the NMR spectroscopic data (δ 5.18 for H-1 and δ 98.5 for C-1 of the 4-O-methyl-D-glucopyranuronosyl unit). 18,19 A portion of this oligosaccharide was converted into its corresponding methyl ester, methyl glycoside, and then analyzed by MS. 25 The mass spectrum of this product showed a fragmentation pattern consistent with the structure methyl 3 Spectroscopic data of the other two acidic oligosaccharides (AOS-2 and AOS-3) were similar to those of the aldobiouronic acid (δ 5.18 for H-1 and δ 98.5 for C-1 of 4-Me-R-D-GlcpA). Methylation analysis of both oligosaccharides showed that their neutral residues were xylobiose and xylotriose.…”

Algal Walls — Composition and Biosynthesis

“…WHYTE and ENGLAR (1971) purified the cellulose from the residue after sequential extraction of Rhodymenia pertusa by dissolution in cuprammonium and reprecipitation. This was methylated and shown by gas-liquid chromatography, mass spectrometry and proton magnetic resonance to consist of (1 -+ 4)-fJ-Dglucopyranose residues.…”

Structural studies of a hemicellulose B fraction (B-2) from the cork of Quercus suber

“…Hakomori methylation (4) of B-2 gave a product with an [a], value of +8.3" indicative of a and P linkages, which was confirmed by the nmr spectra (5). A part of the methylated polysaccharide was reduced with lithium aluminium hydride.…”