Polysaccharide listed

Type I polysaccharide contains an amino sugar, acetyl residues, and is one of the few bacterial polysaccharides to contain D-galacturonic acid, (another being one described by Hassid ). All the pneumococcus polysaccharides listed by Boyd contain acetyl residues, the presence of which in the case of Type I, has a distinct influence on the serological specificity. The structural studies made on the polysaccharide reveal that it may possess a fundamental trisaccharide unit containing two molecules of a uronic acid and one of an acetylamino sugar, together with an additional acetyl residue. 

Dextran - an oi(l->6) polymer of glucose with ot(l->2), ot(l->3), and ot(l->4) branch points. Dextran is the only polysaccharide listed here that does not use activated nucleotide sugars (or derivatives) in making the polymer. The polymerization, catalyzed by the enzyme dextran sucrase, is a transglycosylation of sucrose ... 

Other polymers, such as poly methacrylates, have been studied, as well as esters of naturally occurring polysaccharides. References can be found in the literature cited in the list of further reading. 

The common hemiceUulose components of arborescent plants are listed in Table 3. Xylans, arabinogalactans, and pectic substances are common to all while only traces (if at all) of glucomaimans are found in the cell walls of bamboo. Other polysaccharides are found in trace amounts in wood as well as in bark, growing tissues, and other specialized parts of trees. 

Principal polysaccharide constituent listed. Sugars are D- unless otherwise noted. Ara = arabinose Gal = galactose GalA = galacturonic acid ... 

Many proteins found in nature are glycoproteins because they contain covalently linked oligo- and polysaccharide groups. The list of known glycoproteins includes structural proteins, enzymes, membrane receptors, transport proteins, and immunoglobulins, among others. In most cases, the precise function of the bound carbohydrate moiety is not understood. 

In contrast with the monotonous monosaccharide repeat and the same type of linkage in the polysaccharide structures (1 to 21) described in Sections IV and V, this section deals with rather more complex polymers (23 to 39), which are composed of disaccharide repeats. Further, combining two types of linkages enhances the formation of exotic morphologies not amenable to the former set. The sequence listed in Table II is referred to as -A-B- in Table V while listing... 

The side chains in the latter are flexible disaccharides on account of poor-quality diffraction patterns, their tentative molecular structures are known only from computer modeling.1" On the other hand, well-defined crystal structures are available for gellan and welan, and they can be correlated with the physical properties of the polysaccharides the details are presented here. Their conformation angles are listed in Table VI. 

The ethylene glycol-containing silica precursor has been combined, as mentioned above, with most commercially important polysaccharides and two proteins listed in Table 3.1. In spite of the wide variety of their nature, structure and properties, the jellification processes on addition of THEOS to solutions of all of these biopolymers (Scheme 3.2) had a common feature, that is the formation of monolithic nanocomposite materials, proceeding without phase separation and precipitation. The syner-esis mentioned in a number of cases in Table 3.1 was not more than 10 vol.%. It is worthwhile to compare it with common sol-gel processes. For example, the volume shrinkage of gels fabricated with the help of TEOS and diglyceryl silane was 70 and 53 %, respectively [138,141]. 

Table I lists physical data for a number of the carbamate and ester derivatives of cellulose, chitin, amylose, amylopectin, and dextran synthesized as described in the Experimental Section. The solubility of the polysaccharide starting materials as well as that of the produced derivatives allows for macromolecular characterization through techniques including UV, NMR, IR, high pressure liquid chromatography, etc.

Carbohydrates are diverse with respect to occurrence and size. Familiar mono and disaccharides include glucose, fructose, sucrose (table sugar), cellobiose, and mannose. Familiar polysaccharides are listed in Table 9.1 along with their source, purity, and molecular weight range. 

The zero-shear viscosity r 0 has been measured for isotropic solutions of various liquid-crystalline polymers over wide ranges of polymer concentration and molecular weight [70,128,132-139]. This quantity is convenient for studying the stiff-chain dynamics in concentrated solution, because its measurement is relatively easy and it is less sensitive to the molecular weight distribution (see below). Here we deal with four stiff-chain polymers well characterized molecu-larly schizophyllan (a triple-helical polysaccharide), xanthan (double-helical ionic polysaccharide), PBLG, and poly (p-phenylene terephthalamide) (PPTA Kevlar). The wormlike chain parameters of these polymers are listed in Tables... 

The list of the new gels for which phase transitions are possible is supplemented in the paper by Amiya and Tanaka, who discovered discrete collapse for the most important representatives of biopolymers - chemically crosslinked networks formed by proteins, DNA and polysaccharides [45]. Thus, it was demonstrated that discrete collapse is a general property of weakly charged gels and that the most important factor, which is responsible for the occurrence of this phenomenon, is the osmotic pressure of the system of counter ions. 

Solubility is a very important criterium for the different uses of polysaccharides in pharmacy. Table 4 lists the solubility criteria of some polysaccharides in water. Solutions containing sugars and alcohol generally depress the solubility of polysaccharides. Polysaccharides containing carboxyl groups, i.e., pectins, alginates, and carboxy-methylcellulose, are insoluble at low pH values. They will be precipitated when the pH is lowered below 3. 

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