Polysaccharide hetero

The hetero-l,4-linked xylans (or heteroxylans) constitute a well-characterized group of polysaccharides which form the major components of the hemicellulosic fractions of terrestrial plants (1-4). Softwoods are an exception, where the heteroxylans can be present as a minor component of the total hemicelluloses. They have been isolated from grasses, legumes, ferns, softwoods and hardwoods, and collectively may constitute up to 35% of the total dry weight of higher land plants (4). As such the heteroxylans rank second to cellulose in abundance as naturally occurring organic chemicals in the biosphere. The heteroxylans are closely associated with other... 

Finally, the hetero polysaccharide hexagluconylhexasaminoglycan sulfate was identified as an anticoagulant and antithrombotic material compared to heparin by Sederel and coworkers [521], Derivatives of the polysaccharide dextran containing sulfate, sulfonate or carboxylic groups gave antithrombotic activity due to the presence of these charged groups [483, 522-525],... 

Lipopolysaccharides are biosynthesized according to a common structural architecture (Scheme 4.1). They are composed of a hydrophilic hetero-polysaccharide... 

As well as polymers in which a majority of the sugar residues are Man, a number of other hetero-polysaccharides contain smaller amounts of this sugar. These include bacterial polysaccharides and plant gums and mucilages. However, occasionally a member of the first of these has a high Man content. 

There are several locations for bacterial polysaccharides [82, 83, 256]. The exo-cellular may occur as a capsule or form an extra-cellular slime and are produced by both Gram positive and negative bacteria. Lipopolysaccharides are embedded in the membrane of Gram negative bacteria. Most of the bacterial polysaccharides consist of repeating hetero-oligosaccharyi units which may be branched lipopolysaccharides... 

Definition High m.w. hetero polysaccharide gum produced by a pure-culture fermentation of a carbohydrate with Xanthomonas campestris-, contains D-glucose, D-mannose, and D-glucuronic acid and is prepared as the sodium, potassium, or calcium sait Properties Wh. to cream-colored powd., si. organic odor, tasteless sol. in hot or cold water producing vise, highly-pseudoplastic sol ns. insol. in oils, most org. soivs. vise, 600 cps min. unaffected by high or low pH... 

Classification Polysaccharide gum Definition High m.w. hetero polysaccharide gum produced by a pure-culture fermentation of a carbohydrate with Xanthomonas campesths] contains D-glucose, D-mannose, and D-glucuronic acid and is prepared as the sodium, potassium, or calcium salt... 

Gelling Polysaccharides Gelling polysaccharides are generally more complex than structural polysaccharides in (1). They are hetero polysaccharides built from mixed monomer units and they contain many branched in addition to the straight chains as depicted in Equation 10.20e for starch. Starch, the second most abundant biopolymer, is probably the most important (below). 

The hetero hexamer 6 has been prepared by Schmidt s group it is the Le antigen, and Danishefsky and Randolph have reported the synthesis of the isomeric compound 7 with the substituent linkages to the A/-acetylgIucosamine unit reversed. In this work key use was made of glycal-derived 1,2-epoxides. The structural element 8 of the capsulate polysaccharide of... 

Xiao, Y.G., Wang, Q.H., Liang, J., Yang, B.Y., Li, G.Y., Kuang, H.X. Development and application of a rapid and efficient CZE method coupled with correction factors for determination of monosaccharide composition of acidic hetero-polysaccharides from Ephedra sinica. Phytochem. Anal. 22(2), 103-111 (2011)... 

Hemicellulose is the second most familiar polysaccharide next to cellulose comprising one-fourth to one-third of most plant materials, and in the past twenty years hemicellu-loses have been used as feedstock for producing sugars. Hemicelluloses are mostly hetero-polysaccharides classified according to the sugar residues present, namely xylans, mannans, arabinans and galactans, which are either linear or branched polymers. The most abundant hemicellulose is (3-l->4-D-xylan, which is built from p-l->4-linked D-xylopyranosyl residue, which forms the linear backbone of the polymer. 

The matrix formed in the presence of carbohydrates may be compared with the extracellular matrix of connective tissues. However, the plaque polysaccharides are not glycosaminoglycans but glucans and other high molecular weight homo- and hetero-polysaccharides which are interspersed with the protein component. Examination of the extracellular polysaccharides... 

Several water-soluble, xykn-rich hetero-polysaccharides and their derivatives were measured in this way widi respect to dieir self-assembly behavior at cellulosic LB film surfaces (i.e., dockiiig behavior). The correqionding eiqierimental results ate sununarized in Figure 6. The structure of the xylan derivatives used is given in Figure 2. 

Xylan itself is a hetero-polysaccharide that forms colloids at low solution concentration. Results indicate that a litde xylan is adsorbed, slowly, at... 

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