Insoluble polysaccharides

Gum tragacanth is obtained from the large tap root and branches of a small perennial shmb found in the Middle East, especially Iran. Chemically, it is a mixture of water-insoluble polysaccharides. It is stable to heat, acidity, and aging, and is used extensively in pourable low calorie salad dressings. 

Carbohydrates. Oilseeds contain two types of carbohydrates (qv) soluble mono- and oligosaccharides and largely insoluble polysaccharides. ... 

The oxidation of insoluble polysaccharides was performed by H2O2 in the presence of small amounts of iron tetrasuftbphthalocyanine, a cheap blue dye used as catalyst, to introduce aldehyde and carboxyl ftmctiorrs in polymer chairrs (Figure 30.2). 

Yeast Insoluble Polysaccharide. The structure of an insoluble polysaccharide from the yeast Saccharomyces cerevisiae was investigated by Zechmeister and Toth,90a and also by Hassid, Joslyn and McCready.904 The isolation904 of 2,4,6-trimethyl-D-glucose as the sole product of the hydrolysis of the methylated polysaccharide indicated a chain of gluco-pyranose units joined by 1,3-glucosidic linkages. 

Sanderson, C.J., and Wilson, D.V. (1971) A simple method for coupling proteins to insoluble polysaccharides. Immunology 20,1061-1065. 

Regioselective enzymatic acylation of large, insoluble polysaccharides is still a quite difficult task and therefore it is not surprising that only scant data have been reported up to now, most of them describing reaction outcomes which met with limited success. Nevertheless, enzymatic derivatization of polysaccharides has been performed in nonpolar organic solvents using insoluble polysaccharides with soluble [51] or suspended enzymes [52]. Chemically modified celluloses with either enhanced solubility or more readily accessible hydroxyl groups, like cellulose acetate or hydroxypropyl cellulose, were acylated by CalB, as reported by Sereti and coworkers [53]. However, the same authors failed to modify crystalline cellulose under the same reaction conditions. 

Least Soluble Polysaccharides. As indicated, the most insoluble polysaccharides are those which are reinforcing structural polymers in cell walls. The best example is cellulose, the universal reinforcing struc-... 

In 1954, Jeanes et al.5 reported the formation of glucan(s) by 96 strains of bacteria that were primarily Leuconostoc strains. (There is a question here as to whether they are strains or species, particularly with regard to the formation of different kinds of polysaccharides. The classification of the time was to place them into one species, mesenteroides, that had several different strains. This classification stands today.) The polysaccharides were characterized by various properties such as optical rotation, viscosity, periodate oxidation profile, and physical appearance after alcohol precipitation. The latter were observed to have different appearances, which were described by Jeanes et al.5 in various qualitative terms such as pasty, fluid, stringy, tough, long, short, flocculent, and so on. These differences in appearance provided an early suggestion of differences in structure (see Table I). Both water-soluble and water-insoluble polysaccharides were formed, and some strains seemed to form more than one kind of polysaccharide, as judged by their water solubility and by differences in the amount of alcohol needed to precipitate them. 

Disaccharides and even some insoluble polysaccharides are substrates, but not monosaccharides. Cellobiose oxidase is unusual among flavoproteins, as it stabilises the red anionic flavin semiquinone and forms a sulphite adduct, yet appears to produce the superoxide anion as its primary reduced oxygen product. 

Yeast Insoluble Polysaccharide.—The skeletal polysaccharide of yeast has been shown to be a polyglucose in which the residues are joined by 1,3-glycosidic linkages.119 An indication that the molecular weight was of the order of 8,000 (36 units) was obtained from the specific viscosity, and a closed-chain type of structure for the molecule was suggested as no end-groups were found in the methylation studies. 

Yeast insoluble-polysaccharide Methyl ether Viscosity m-Cresol 8,000( ) 36 — Closed chain 59... 

Hemicelluloses, the second group of plant-cell constituents, are water-insoluble polysaccharides. During the first stage of attack, hemicelluloses disappear more rapidly than cellulose. Later, hemicelluloses slow down in degradation owing to their heterogeneity. Fungi, bacteria, and actinomycetes are able to break down hemicelluloses by... 

There are many methods for covalently linking carbohydrate to enzymes, most of these having been developed for immobilization of enzymes on insoluble polysaccharide supports (2.) For our work we... 

Attachment of enzymes to activated insoluble polysaccharides is routinely carried out at pH 9.0, and this pH has been found to be suitable for synthesis of most soluble dextran-enzyme... 

Table I shows a comparison of the conditions for coupling of enzymes to soluble and insoluble polysaccharides.

Preparation of Soluble and Insoluble Polysaccharide-Enzyme Conjugates... 

Conditions or procedure Insoluble polysaccharide Soluble polysaccharide ... 

Zymosan An insoluble polysaccharide derived from the cell walls of fungi. More... 

Bethell GS, Ayers JS, Hearn MTW, and Hancock WS. Investigation of the activation of various insoluble polysaccharides with l,l -carbonyldiimidazole and of the properties of the activated matrices. J. Chromatogr. 1981 219 361-371. 

This chapter describes dental caries (tooth decay) and its causes. Sucrose and other mono- and disaccharides are metabolized to acid (lactate) by bacteria that remain in stagnation areas of the teeth. Rats and hamsters fed a 50% sucrose diet developed a caries-sensitive, predominantly gram-positive microbiota that became caries resistant when the rodents were fed penicillin (Sect. 1). Further studies identified Streptococcus mutans (S. mutans) as the etiological agent. This organism synthesizes an insoluble polysaccharide capsule that is stable and retains lactate at the enamel surface (Sect. 2). The key enzyme, glucosyl transferase, is related to salivary amylase which adheres to oral bacteria and enhances bacterial acid production. The chapter concludes with a discussion of salivary and other factors responsible for the marked variation observed in individual caries experience (Sect. 3). 

---