Polysaccharides, carboxymethylated

Ozturk DC, Kazan D, Erarslan A (2002) Stabilization and flmctional properties of Escherichia coli peniciUinG acylase by covalent conjugation of anionic polysaccharide carboxymethyl cellulose. World J Microbiol Biotechnol 18 881-888... 

Recent progress of basic and application studies in chitin chemistry was reviewed by Kurita (2001) with emphasis on the controlled modification reactions for the preparation of chitin derivatives. The reactions discussed include hydrolysis of main chain, deacetylation, acylation, M-phthaloylation, tosylation, alkylation, Schiff base formation, reductive alkylation, 0-carboxymethylation, N-carboxyalkylation, silylation, and graft copolymerization. For conducting modification reactions in a facile and controlled manner, some soluble chitin derivatives are convenient. Among soluble precursors, N-phthaloyl chitosan is particularly useful and made possible a series of regioselective and quantitative substitutions that was otherwise difficult. One of the important achievements based on this organosoluble precursor is the synthesis of nonnatural branched polysaccharides that have sugar branches at a specific site of the linear chitin or chitosan backbone [89]. 

Sodium carboxymethyl chitin and phosphoryl chitin had most evident influences on the crystallization of calcium phosphate from supersaturated solutions. They potently inhibited the growth of hydroxyapatite and retarded the rate of spontaneous calcium phosphate precipitation. These chitin derivatives were incorporated into the precipitate and influenced both the phase and morphology of the calcium phosphate formed (flaky precipitate resembling octacalcium phosphate instead of spherical clusters in the absence of polysaccharide) [175]. 

Biodegradable drilling fluid formulations have been suggested. These are formulations of a polysaccharide in a concentration insufficient to permit a contaminating bacterial proliferation, namely a high-viscosity carboxymethyl-cellulose sensitive to bacterial enzymes produced by the degradation of the polysaccharide [1419]. 

Several anionic carbohydrate polymers (e.g., carboxymethyl cellulose, xanthomonas campestris polysaccharide, cellulose sulfate ester, etc.) do not adsorb from fresh water solutions, but their adsorption in saline solutions plays an... 

Polyelectrolytes have recently found application in the development of pH sensitive liposomal controlled release systems. This application arises from the fact that polyelectrolytes may be used both to stabilize liposomes, and to disrupt liposomes in a pH dependent manner. Although the use of liposomes in oral pharmaceutical compositions has been discussed [424], liposomes generally suffer from poor stability and are therefore prone to leakage of the entrapped active agents. To overcome this problem, several authors have stabilized the liposomes using polyelectrolytes. For example, Tirrell and coworkers have employed ionene [425], and polyethylene imine) [426] to stabilize liposomes. Similarly, Sato and coworkers have studied maleic acid copolymers [427], and Sumamoto and coworkers have studied liposomes [428] coated with polysaccharides. In related work, Kondo and coworkers have emphasized the use of carboxymethyl chitin to produce artificial red blood cells [429-435]. 

In describing and interpreting some of the more important properties of plant galactomannans, comparisons will be made with structurally similar polysaccharides, including the closely related glucomannans and galactoglucomannans, and those based on (1 — 4)-/3-D-xylan main-chains (for example, the arabinoxylans) and (1 — 4)-/3-D-glucan main-chains [for example, the amyloids and sodium 0-(carboxymethyl)cellulose]. 

The interaction with polysaccharides closely related structurally to galactomannans has been studied less for Xanthomonas polysaccharide than for agar. No interaction is observed between Xanthomonas polysaccharide and sodium O-(carboxymethyl)-cellulose (degree of substitution 0.7), probably because of electrostatic repulsion between the two negatively charged polysaccharides.178 Xanthomonas polysaccharide can, however, interact with polysaccharides based on /3-l>(l — 4)-linked D-glucan backbones, as... 

Milk fat and milk solids-not-fat (MSNF) are most commonly obtained from cream and condensed skim milk, but may also be obtained from a combination of fluid milk, condensed whole milk, frozen cream, frozen condensed milk, nonfat dry milk, dry whole milk, and butter. Sweeteners used in the mix normally include a combination of liquid or dry sucrose, corn sweetener, high-fructose corn sweetener, and corn syrup solids. Ice cream stabilizers are formulated to contain one or more polysaccharide hydrocolloids, e.g., carboxymethyl cellulose, locust bean gum, carageenin, alginate, and other gums. Ice cream emulsifiers normally contain monoglycerides and diglycerides of palmitic and stearic... 

Rogovin, Z. A., and U. Zhun-Zhui Structure and properties of cellulose and its esters. LXXXV. Synthesis of new derivatives of cellulose and other polysaccharides. IV. Synthesis of graft copolymers of carboxymethyl cellulose and caprolactam. Vysokomolekulyarnye Soedineniya 1, 1630 (1959). 

For other polysaccharides such as chitosan a high antimicrobial activity has been described - mainly against Escherichia coli and Staphylococcus aureus [153,154]. This activity of chitosan is the basis for the development of materials for wound healing, e.g., in combination with N,0-(carboxymethyl)chitosan and collagen [155]. 

CMD and mixed derivatives based on CMD may be used for the fixation of antibiotics and enzymes on a polysaccharide matrix. A procedure was developed for amidation of CMD and its ethyl ester (CMDEE) with various aromatic amines in dioxane (100 °C), ethanol (78 °C), n-propanol (97 °C) and 2-propanol (82 °C) in the presence of a small amount of water [301]. CMDEE reacts with aliphatic and aromatic amines but in the case of amino acids the degree of amidation depends on the position of the amino moieties in the acids [302,303]. The DS decreases from S-, y-, /3, to a-amino acids. For the reaction with a-amino acids, carboxymethyl and carboxyethyl dextran azides are used [304],... 

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