THE CONSTITUTION OF A POLYURONIDE HEMICELLULOSE FROM WHEAT STRAW

1952 ◽  
Vol 30 (9) ◽  
pp. 698-710 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Molar Ratio ◽  
Acid Complex ◽  
Glycosidic Bonds ◽  
A Chain ◽  
End Group

The structure of a polyuronide hemicellulose from wheat straw containing xylose, arabinose, and hexuronic acid units has been investigated. Graded hydrolysis preferentially removed anhydro-L-arabinose units leaving a xylan to which uronic acid units were attached. Methylation and hydrolysis yielded 2,3,4-trimetliyl xylose (2.7%) indicating one nonreducing end group per 37 units; 2,3,5-trimethyl-L-arabinose, 2,3-dimethyl-D-xylose, and 2-methyl-D-xylose were found in a molar ratio 1:5:1. In addition, a methylated uronic acid complex was recovered which on extensive hydrolysis yielded an aldobiuronic acid. The latter, on reduction with sodium borohydride, yielded 2,3,4-trimethyl glucose (1 mole) and 2-methyl xylose (1 mole); the structure 2-methyl 3[2,3,4-trimethyl α-D-glucuronosido] D-xylose was therefore indicated for the methylated aldobiuronic acid.A structure for the hemicellulose is proposed which consists of approximately 32 anhydro-D-xylose units linked β 1,4- in a chain to which five anhydro-L-arabinose and three D-glucuronic acid units are attached as side groups by 1,3-glycosidic bonds. Results of periodate oxidation and estimation of reducing power support the proposed structure.

CONSTITUTION OF A POLYURONIDE HEMICELLULOSE FROM WHEAT LEAF

1954 ◽  
Vol 32 (2) ◽  
pp. 186-194 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Uronic Acid ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Degree Of Polymerization ◽  
Acid Anhydride ◽  
Alkaline Extraction ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Acid Unit

Crude hemicellulose of mature wheat leaves has been prepared by alkaline extraction of leaf holocellulose. Purification by repeated complexing with Fehling′s solution yielded a polyuronide hemicellulose [Formula: see text] composed of D-xylose (88.5%), L-arabinose (6.90%), and uronic acid anhydride (5.27%). Methylation studies indicated a molecular structure comprising a main xylan chain of 30 an-hydro- D-xylose residues to which three L-arabinose residues and one D-glucuronic acid unit were attached as side chains by glycosidic linkages. Periodate oxidation data supported the proposed structure and the yield of formic acid indicated a molecule containing approximately 32 sugar residues. Estimations of the degree of polymerization of the molecule by measurements of viscosity and reducing power agreed with the foregoing values. The structure of the hemicellulose closely resembled that of one isolated previously from wheat straw.

CONSTITUTION OF AN ACIDIC XYLAN FROM TAMARACK (LARIX LARICINA)

1960 ◽  
Vol 38 (12) ◽  
pp. 2402-2409 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Molecular Weight ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Degree Of Polymerization ◽  
Single Units ◽  
Larix Laricina ◽  
Glycosidic Bonds

An acidic xylan isolated from tamarack wood contained arabinose, xylose, and uronic acid (1:17:3) and was homogeneous on examination by electrophoresis and sedimentation. Molecular weight estimations by four different methods showed a degree of polymerization of 20. Methylation and periodate oxidation showed that the xylan consisted of ca. 16 β-D-xylopyranose units joined by 1 → 4 glycosidic bonds with the possible occurrence of one 1 → 3 linkage. To this unbranched structure were attached as side branches, three single units of 4-O-methyl-D-glucuronic acid through C2 and one unit of L-arabofuranose through C3.

scholarly journals Structural studies on heparan sulphate from human lung fibroblasts. Characterization of oligosaccharides obtained by selective periodate oxidation of d-glucuronic acid residues followed by scission in alkali

1980 ◽  
Vol 191 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Ingrid Sjöberg ◽  
Lars-Ȧke Fransson
Keyword(s):  
Uronic Acid ◽  
Glucuronic Acid ◽  
Human Lung ◽  
General Structure ◽  
Heparan Sulphate ◽  
Periodate Oxidation ◽  
Exchange Chromatography ◽  
Lung Fibroblasts ◽  
Human Lung Fibroblasts ◽  
Iduronic Acid

1. 3H- and 35S-labelled heparan sulphate was isolated from monolayers of human lung fibroblasts and subjected to degradations by (a) deaminative cleavage and (b) periodate oxidation/alkaline elimination. Fragments were resolved by gel- and ion-exchange-chromatography. 2. Deaminative cleavage of the radioactive glycan afforded mainly disaccharides with a low content of ester-sulphate and free sulphate, indicating that a large part (approx. 80%) of the repeating units consisted of uronosyl-glucosamine-N-sulphate. Blocks of non-sulphated [glucuronosyl-N-acetyl glucosamine] repeats (3–4 consecutive units) accounted for the remainder of the chains. 3. By selective oxidation of glucuronic acid residues associated with N-acetylglucosamine, followed by scission in alkali, the radioactive glycan was degraded into a series of fragments. The glucuronosyl-N-acetylglucosamine-containing block regions yielded a compound N-acetylglucosamine–R, where R is the remnant of an oxidized and degraded glucuronic acid. Periodate-insensitive uronic acid residues were recovered in saccharides of the general structure glucosamine–(uronic acid–glucosamine)n–R. 4. Further degradations of these saccharides via deaminative cleavage and re-oxidations with periodate revealed that iduronic acid may be located in sequences such as glucosamine-N-sulphate→iduronic acid→N-acetylglucosamine. Occasionally the iduronic acid was sulphated. Blocks of iduronic acid-containing repeats may contain up to five consecutive units. Alternating arrangements of iduronic acid- and glucuronic acid-containing repeats were also observed. 5. 3H- and 35S-labelled heparan sulphates from sequential extracts of fibroblasts (medium, EDTA, trypsin digest, dithiothreitol extract, cell-soluble and cell-insoluble material) afforded similar profiles after both periodate oxidation/alkaline elimination and deaminative cleavage.

CONSTITUTION OF A DEGRADED POLYSACCHARIDE FROM WHEAT BRAN

1957 ◽  
Vol 35 (2) ◽  
pp. 108-114 ◽  
Author(s):  
J. Schmorak ◽  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Acid Hydrolysis ◽  
Wheat Bran ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Glycosidic Bond ◽  
Cellulolytic Enzyme ◽  
Acidic Polysaccharide ◽  
Hydrolysis Of ◽  
End Group ◽  
Acid Unit

Graded acid hydrolysis of a soluble wheat bran hemicellulose containing L-arabinose (50%), D-xylose (38.5%), and D-glucuronic acid (9.0%) preferentially removed the L-arabinose giving an insoluble acidic polysaccharide in approximately 25% yield by weight. Methylation studies, periodate oxidation data, and hypoiodite end group estimations showed that the degraded polysaccharide was composed of repeating units of 7-8 D-xylopyranose residues joined by β,1 → 4 linkages. To this repeating unit, one D-glucuronic acid unit was attached by a 1 → 2 glycosidic bond. The cellulolytic enzyme of Myrotheciumverrucaria, which is specific for β,1 → 4 glycosidic linkages, hydrolyzed the degraded polysaccharide although it had no effect on the parent hemicellulose

CONSTITUTION OF A WATER SOLUBLE HEMICELLULOSE FROM AMERICAN BEECHWOOD (FAGUS GRANDIFOLIA)

1957 ◽  
Vol 35 (6) ◽  
pp. 556-564 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Average Molecular Weight ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Fagus Grandifolia ◽  
Water Soluble ◽  
Hot Water ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Homogeneous Fraction ◽  
Hydrolysis Of

Extraction of beechwood chlorite holocellulose with hot water yielded a hemicellulose in 13.4% yield (based on original extractive-free wood) containing D-xylose 72%, D-galactose 11.0%, and uronic acid 13.2%. Purification of the crude hemicellulose by complexing with Fehling's solution yielded a chemically homogeneous fraction containing D-xylose 83% and 4-O-methyl-D-glucuronic acid 15.5%. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose in a molar ratio of 2:35:3:5. On the basis of the methylation data, periodate oxidation, reducing power determinations, and weight average molecular weight values a possible structure for the hemicellulose is proposed.

Galactosamine Polymer Isolated from the Cell Wall of Neisseria sicca

1972 ◽  
Vol 50 (4) ◽  
pp. 345-351 ◽  
Author(s):  
G. A. Adams ◽  
A. S. Chaudhari
Keyword(s):  
Cell Wall ◽  
Optical Rotation ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Branch Points ◽  
Weight Estimation ◽  
Glycosidic Bonds ◽  
A Value ◽  
Neisseria Sicca ◽  
End Group

A D-galactosamine polymer having a molar ratio of galactosamine–acetyl–phosphorus (1.0:1.0:0.35) has been isolated from the cell wall of Neisseria sicca. Its homogeneity was established by free-boundary electrophoresis, ultracentrifugal sedimentation, and gel permeation chromatography. Molecular weight estimation by reducing end group assay gave a value of [Formula: see text] 18 500. Methylation analysis indicated that the main glycosidic linkages were (1 → 4) and (1 → 6) with a minimum of 10% branch points. The glycosidic bonds were indicated as being in the α configuration by the high positive optical rotation of the polysaccharide and also from infrared spectrum evidence. Both the acetyl and phosphate contents were relatively unchanged by the Hakamori methylation procedure. Although galactosamine polymers have been found in a number of fungi, the present instance appears to be the first report of their presence in bacteria.

CRYSTALLINE XYLANS FROM STRAWS

1953 ◽  
Vol 31 (9) ◽  
pp. 793-800 ◽  
Author(s):  
C. T. Bishop
Keyword(s):  
Wheat Straw ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Basic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Uronic Acid Content ◽  
Crystallization Procedure ◽  
Diffraction Patterns

Hemicelluloses, extracted from barley, flax, oat, rye, and wheat straw holo-celluloses, were composed predominantly of anhydro-D-xylose units, with small amounts of L-arabinose and D-glucuronic acid. The hemicelluloses had degrees of polymerization ranging from 55 for oat to 185 for rye and were shown to be linear polysaccharides. Autoclaving in distilled water at 120 °C. yielded crystalline xylans from barley, rye, and wheat straw hemicelluloses. The basic structure of the hemicellulose was maintained in the crystalline xylans, which gave identical X-ray diffraction patterns and had similar, linear structures. The crystallization procedure was found to degrade the hemicellulose, removing D-xylose, L-arabinose, and D-glucuronic acid as components of hydrolytic fragments and leaving a pure xylan one sixth to one third the length of its parent hemicellulose. Depending on uronic acid content, the five hemicelluloses in water gave pH values ranging from 2–5 with consequent variations in resistance to hydrolysis during autoclaving

USE OF LIQUID AMMONIA IN THE FRACTIONATION OF WHEAT STRAW HOLOCELLULOSE

1950 ◽  
Vol 28b (12) ◽  
pp. 753-761 ◽  
Author(s):  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Potassium Hydroxide ◽  
Galacturonic Acid ◽  
Uronic Acid ◽  
Room Temperature ◽  
Liquid Ammonia ◽  
Cold Water ◽  
Acid Anhydride ◽  
Acid Complex ◽  
Molar Ratios

Wheat straw holocellulose, after soaking in liquid ammonia for 36 hr. at room temperature, was fractionated by successive extractions with cold water, 0.5% sodium carbonate, 0.5% potassium hydroxide, and 2.2% potassium hydroxide. Pretreatment with liquid ammonia increased the material soluble in cold water from 3% to 20.2%. Hemicellulose fractions were precipitated from the extracts by ethanol. A complete analytical balance was obtained by estimating ash, pentosan, uronic acid anhydride, acetyl, and methoxyl contents of the original holocellulose, of each of the fractions and of the residue. Analyses of the isolated fractions showed some systematic differences, with pentosan contents increasing and uronic acid anhydride decreasing progressively in the alkali soluble fractions. D-xylose, L-arabinose, D-glucose, D-galactose, and hexuronic acid in approximate molar ratios of 40:7:2:1:4 were found in the hemicellulose fractions. The presence of the sugars was confirmed by isolation of crystalline derivatives. A uronic acid complex, resistant to hydrolysis, was isolated and the components shown to be D-xylose and a monomethoxyl galacturonic acid.

CONSTITUTION OF A HEMICELLULOSE FROM WHEAT BRAN

1955 ◽  
Vol 33 (1) ◽  
pp. 56-67 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Oxalic Acid ◽  
Wheat Bran ◽  
Uronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Degree Of Polymerization ◽  
Alkaline Extraction ◽  
Acidic Polysaccharide ◽  
Simultaneous Production ◽  
Hydrolysis Of

The hemicellulose prepared from wheat bran by alkaline extraction was an acidic polysaccharide containing arabinose (50.0%), xylose (38.5%), and uronic acid (9.0%). Graded hydrolysis with 0.02 N oxalic acid preferentially released 65% of the arabinose with only a small simultaneous production of xylose. Hydrolysis of the full methylated hemicellulose yielded 2,3,4-tri-O-methyl-, 2,3-di-O-methyl-, 2-O-methyl-, and free D-xylose; 2,3,5-tri-O-methyl-, 2,5-di-O-methyl-, and probably 3- and 5-O-methyl-L-arabinose. These data, together with those from periodate oxidation, strongly suggested that the molecule was a highly branched araboxylan. Viscosity measurements and reducing power determinations indicated a degree of polymerization of 300.

scholarly journals Characterization and Antioxidant Activity of a Low-Molecular-Weight Xanthan Gum

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 730 ◽  
Author(s):  
Hu ◽  
Wang ◽  
Yu ◽  
He ◽  
Qiao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hydroxyl Radicals ◽  
Xanthan Gum ◽  
Glucuronic Acid ◽  
Reducing Power ◽  
Monosaccharide Composition ◽  
Molar Ratio ◽  
Low Molecular Weight ◽  
Oxygen Species ◽  
Superoxide Anions

In the present work, a low-molecular-weight xanthan gum (LW-XG) was successfully obtained via biodegradation of commercial xanthan by the endophytic fungus Chaetomium globosum CGMCC 6882. The monosaccharide composition of LW-XG was glucose, mannose, and glucuronic acid in a molar ratio of 1.63:1.5:1.0. The molecular weight of LW-XG was 4.07 × 104 Da and much smaller than that of commercial xanthan (2.95 × 106 Da). Antioxidant assays showed that LW-XG had a good scavenging ability on DPPH radicals, superoxide anions, and hydroxyl radicals and good ferric reducing power. Moreover, LW-XG exhibited excellent protective effect on H2O2-injured Caco-2 cells. Results of this work suggested that LW-XG could be used in foods or pharmaceuticals to alleviate and resist the oxidative damage induced by the overproduction of reactive oxygen species.

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