THE STRUCTURE OF THE EXTRACELLULAR POLYSACCHARIDE OF AZOTOBACTER INDICUM

1963 ◽  
Vol 41 (11) ◽  
pp. 2826-2835 ◽  
Author(s):  
V. M. Parikh ◽  
J. K. N. Jones

The extracellular polysaccharide of the Azotobacter indicum has been shown to be a mixture of two polymers of which the acidic polymer was a major fraction. The acidic polymer contained D-glycero-D-mannoheptose in the molar ratio of 1:1:1 plus traces of mannose. It consumed 1 mole of sodium metaperiodate per mole of an average anhydroaldose unit and released 0.95 moles of formaldehyde per anhydroheptose unit. Reduction of the oxidized polymer followed by hydrolysis yielded D-glucose, glycerose, glycolaldehyde, and glycerol. Complete fission of the methylated polymer yielded 2,3-di-O-methyl-D-glucuronic acid, 2,4,6,-tri-O-methyl α-D-glucose and 3,4,6,7-tetra-O-methyl D-glycero-D-mannoheptose. Partial hydrolysis of the methylated polymer produced a methylated aldotriouronic acid composed of 1 mole each of 2,3-di-O-methyl-D-glucuronic acid, 2,4,6-tri-O-methyl-D-glucose and 3,4,6,7-tetra-O-methyl D-glycero-D-mannoheptose. A methylated aldobiouronic acid was also produced and was shown to be composed of 2,3-di-O-methyl-D-glucuronic acid and 2,4,6-tri-O-methyl D-glucose.On the basis of these results it is proposed that the polysaccharide is a linear molecule composed of repeating units of D-glucuronic acid, D-glucose, and D-glycero-D-mannoheptose.

1959 ◽  
Vol 37 (5) ◽  
pp. 922-929 ◽  
Author(s):  
A. L. Currie ◽  
T. E. Timell

The seed hairs of kapok (Ceibapentandra) on alkaline extraction have yielded a hemicellulose composed of xylose and uronic acid residues. Partial hydrolysis of the polysaccharide gave 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose, 4-O-methyl-D-glucuronic acid, and, probably, galacturonic acid. Hydrolysis of the fully methylated hemicellulose yielded a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid)-3-O-methyl-D-xylopyranose in a molar ratio of 1.1:38:1:6. The number-average D.P. of the native and the methylated polysaccharides was 177 and 124, respectively. On the basis of this and other evidence it is suggested that the average hemicellulose molecule contains approximately 180 1,4-linked β-D-xylopyranose residues, one eighth of which carry a single terminal side chain of 4-O-methyl-D-glucuronic acid, attached through an α-glycosidic bond to C2 of the xylose. The xylan framework contains, on the average, slightly less than two branching points per macromolecule, most of them probably originating from C3. The number of acid side chains and branches is twice as large as that of the otherwise similar 4-O-methyl glucuronoxylan present in the seed hairs of milkweed floss.


1958 ◽  
Vol 36 (11) ◽  
pp. 1467-1474 ◽  
Author(s):  
J. K. Gillham ◽  
T. E. Timell

The wood of white elm (Ulmusamericana) has been found to contain less xylan than most other hardwoods. Partial hydrolysis of the hemicellulose component yielded an aldotriouronic acid, a glucuronosyl xylose, 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose, 4-O-methyl-D-glucuronic acid, and galacturonic acid.Hydrolysis of the fully methylated polysaccharide gave a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid)-3-O-methyl-D-xylopyranose in a molar ratio of 6:124:1:14. The number-average degree of polymerization of the methylated hemicellulose was 133 and that of the native polymer 185. On the basis of this and other evidence it is suggested that the xylan is linear and contains 185 1,4-linked β-D-xylopyranose residues, every seventh of which carries a single terminal side chain of 4-O-methyl-D-glucuronic acid attached by an α-glycosidic bond through C2 of the xylose. The number of acid groups is larger than in other hardwood hemicelluloses so far studied.


1956 ◽  
Vol 34 (3) ◽  
pp. 338-344 ◽  
Author(s):  
E. L. Falconer ◽  
G. A. Adams

Partial hydrolysis of hemicellulose B from oat hulls yielded two aldobiouronic acids, which were identified as 2-O-(4-O-methyl-α-D-glucopyruronosyl)-D-xylose and 2-O-(α-D-glucopyruronosyl)-D-xylose respectively. In addition, two aldotriouronic acids were isolated, one yielding on hydrolysis xylose and 4-O-methyl-glucuronic acid, and the other, xylose, galactose, and glucurone.


1962 ◽  
Vol 40 (12) ◽  
pp. 2204-2213 ◽  
Author(s):  
A. Misaki ◽  
S. Kirkwood ◽  
J. V. Scaletti ◽  
F. Smith

The extracellular polysaccharide isolated from cultures of Xanthomonas oryzae is composed of D-glucose (5 molecular proportions), D-glucuronic acid (2 molecular proportions), and D-mannose (5 molecular proportions). Acid hydrolysis of this polysaccharide, which contains 0.3% combined pyruvic acid, yields 2-O-β-D-glucopyranosyluronic acid D-mannose, which has been characterized as its crystalline fully methylated β-glycoside. Hydrolysis of the methylated polysaccharide gives 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions), 2,3,4-tri-O-methyl-D-glucuronic acid (1 molecular proportion), 2,3,6-tri-O-methyl-D-glucose (4 molecular proportions), 3,4,6-tri-O-methyl-D-mannose (2 molecular proportions), 2,6-di-O-methyl-D-glucose (3 molecular proportions), 2,3-di-O-methyl-D-glucose (1 molecular proportion). The polyalcohol derived from the polysaccharide by periodate oxidation followed by sodium borohydride reduction gives upon acid hydrolysis glycerol (2 molecular proportions), erythritol (1 molecular proportion), and D-glucose (1 molecular proportion). The general structural significance of these findings is discussed.


1968 ◽  
Vol 46 (21) ◽  
pp. 3407-3411 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer

The two exocellular polysaccharides of Candida bogoriensis contain D-mannose, D-fucose, L-rhamnose, D-glucuronic acid, and D-galactose residues. The main heteropolymer (> 80%) has an α-D-(1 → 3)-linked mannan main-chain as shown by successive Smith degradations. Partial hydrolysis of the heteropolymers provided several methylpentose-containing oligosaccharide fragments corresponding to possible side-chain components.


1963 ◽  
Vol 41 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
A. R. Mills ◽  
T. E. Timell

An arabino-4-O-methylglucuronoxylan (10:70:12), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.2:1:3) have been isolated in yields of 8.0, 1.0, and 8.1% from the wood of Engelmann spruce (Picea engelmanni). The xylan consisted of a linear framework of (1 → 4)-linked β-D-xylose residues to which were directly attached single side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues. The galactoglucomannans were both composed of a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues, some of which carried directly attached side chains of (1 → 6)-linked α-D-galactopyranose residues. Partial hydrolysis of the water-soluble galactoglucomannan yielded, among other oligosaccharides, a trisaccharide composed of galactose, glucose, and mannose residues. It is concluded that the main polysaccharides in the wood of Engelmann spruce are the same as those in most other gymnosperms. In the bark of this tree, the water-soluble galactoglucomannan is replaced by one or several polysaccharides of an entirely different composition.


1959 ◽  
Vol 37 (5) ◽  
pp. 893-898 ◽  
Author(s):  
T. E. Timell

Partial hydrolysis of the main hemicellulose constituent of sugar maple (Acersaccharum) has yielded D-xylose, D-galacturonic acid, 4-O-methyl-D-glucuronic acid, and 2-O-(4-O-methyl-α-D-glucosyluronic acid)-D-xylose. Hydrolysis of the fully methylated polysaccharide gave a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucosyluronic acid)-3-O-methyl-D-xylose in a mole ratio of 3:111:1:12. The number-average degrees of polymerization of the native and the methylated polysaccharide were 205 and 149, respectively. These data indicate that the hemicellulose is composed of a linear chain of 1,4-linked β-D-xylose residues and that on the average every tenth residue of the chain carries a terminal 4-O-methyl-D-glucuronic acid residue attached through its C2. The structure of the polysaccharide is similar to that of the main hemicellulose component of European beech, white birch, and yellow birch.


1961 ◽  
Vol 39 (8) ◽  
pp. 1683-1694 ◽  
Author(s):  
I. R. Siddiqui ◽  
G. A. Adams

Growth of Gibberellafujikuroi (Fusariummoniliforme) on a glucose medium produced au extracellular polysaccharide containing D-glucose, D-mannose, D-galactose, D-glucuronic acid (molar ratio 1.0:1.1:1.3:0.6), and possibly D-mannuronic acid. Protein was retained tenaciously by the polysaccharide and several deproteinization methods reduced the nitrogen content only slightly. Methylation studies showed that the polysaccharide was highly branched with D-glucose and D-mannose forming the non-reducing ends in the molecule. Most of the D-mannose and D-galactose units were joined by 1 → 2 and 1 → 6 linkages with some branching also at C2 and C6 positions; D-galactose occurred exclusively in the furanose form. D-Glucose units were joined by 1 → 2 and 1 → 3 linkages. The D-glucuronic acid residues were mainly non-terminal and were attached to both D-galactose and D-mannose units. Periodate oxidation studies supported the foregoing conclusions.


1961 ◽  
Vol 39 (5) ◽  
pp. 1059-1066 ◽  
Author(s):  
J. K. N. Jones ◽  
C. B. Purves ◽  
T. E. Timell

A 4-O-methylglucuronoxylan has been isolated in almost quantitative yield from the wood of trembling aspen (Populustretmuloides Michx.) The hemicellulose was electrophoretically homogeneous and had a number-average degree of polymerization of 212. Partial hydrolysis gave D-xylose, galacturonic acid, 4-O-methylglucuronic acid, and 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose. Methanolysis and hydrolysis of the fully methylated polysaccharide, which contained 108 xylose residues per average molecule, gave 2-O-methylxylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and methyl 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid) -3-O-methyl-D-xylopyranoside in a mole ratio of 0.2:95:1:11. It is concluded that the hemicellulose contained a linear framework of approximately 200 (1 → 4)-linked β-D-xylopyranose residues and that, on the average, every ninth xylose unit carried a (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid residue directly attached to the xylan backbone. The polysaccharide is evidently similar to the 4-O-methylglucuron-oxylans occurring in the wood of all arborescent angiosperms so far investigated.


1961 ◽  
Vol 39 (7) ◽  
pp. 1408-1418 ◽  
Author(s):  
A. K. Mukherjee ◽  
D. Choudhury ◽  
P. Bagchi

The water-soluble polysaccharide extracted from the kernel of green palmyra palm nut (Borassusflabellifer Linn.) was shown to be composed of D-galactose and D-mannose in the proportion of 1:2.4. Hydrolysis of the fully methylated galactomannan yielded 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-mannose, and 2,3-di-O-methyl-D-mannose in the molar ratio of 1:1.4:0.95. Partial hydrolysis of the galactomannan afforded 4-O-β-D-mannopyranosyl-D-mannose, 6-O-α-D-galactopyranosyl-D-mannose, and two trisaccharides. Based on these results a structural formula for the galactomannan has been proposed, additional evidence for which was adduced from periodate-oxidation studies.


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