Methylation analysis of cellulose sulphates

Gohdes, Michael; Mischnick, Petra; Wagenknecht, W.

doi:10.1016/s0144-8617(97)00020-9

Cited by 21 publications

(13 citation statements)

References 19 publications

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“…CS10 synthesis started with a cellulose triacetate (degree of polymerization of about 300, corresponding to a molecular mass of 50 kDa with respect to the cellulose backbone) which then was partially deacetylated with 1,6-diaminohexane and subsequently sulfated (30,31). Structural analysis of the cellulose sulfates has been described elsewhere (21,22). The chemical characteristics of the cellulose sulfates are listed in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of Chondroitin-4-Sulfate-Specific Adhesion of Plasmodium falciparum -Infected Erythrocytes by Sulfated Polysaccharides

et al. 2005

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Adhesion of Plasmodium falciparum-infected erythrocytes to placental chondroitin 4-sulfate (CSA) has been linked to the severe disease outcome of pregnancy-associated malaria. Soluble polysaccharides that release mature-stage parasitized erythrocytes into the peripheral circulation may help elucidate these interactions and have the potential to aid in developing therapeutic strategies. We have screened a panel of 11 sulfated polysaccharides for their capacities to inhibit adhesion of infected erythrocytes to CSA expressed on CHO-K1 cells and ex vivo human placental tissue. Two carrageenans and a cellulose sulfate (CS10) were able to inhibit adhesion to CSA and to cause already bound infected erythrocytes to de-adhere in a dose-dependent manner. CS10, like CSA and in contrast to all other compounds tested, remained bound to infected erythrocytes after washing and continued to inhibit binding. Both carrageenans and CS10 inhibited adhesion to placental tissue. Although highly sulfated dextran sulfate can inhibit CSA-mediated adhesion to CHO cells, this polysaccharide amplified adhesion to placental tissue severalfold, demonstrating the importance of evaluating inhibitory compounds in systems as close to in vivo as possible. Interestingly, and in contrast to all other compounds tested, which had a random distribution of sulfate groups, CS10 exhibited a clustered sulfate pattern along the polymer chain, similar to that of the undersulfated placental CSA preferred by placental-tissue-binding infected erythrocytes. Therefore, the specific antiadhesive capacity observed here seems to depend not only on the degree of charge and sulfation but also on a particular pattern of sulfation.

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Section: Methodsmentioning

confidence: 99%

Inhibition of Chondroitin-4-Sulfate-Specific Adhesion of Plasmodium falciparum -Infected Erythrocytes by Sulfated Polysaccharides

et al. 2005

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“…Acidic acetylation (Gohdes 1997) After cooling to r. t., the solution was concentrated in a stream of nitrogen and then co-evaporated with acetonitrile. The residue was dissolved in 250 lL of acetic anhydride and 250 lL of TFA was added to acetylate the sample at 60°C for 30 min.…”

Section: Alditol Acetatesmentioning

confidence: 99%

Critical re-investigation of the alditol acetate method for analysis of substituent distribution in methyl cellulose

Voiges

Adden

Rinken³

et al. 2012

Cellulose

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The alditol acetate method is a common procedure for sugar analysis, also applied to determine the substituent distribution in monomer units of polysaccharide ethers like methyl cellulose by gas liquid chromatography. Consisting of several preparation and work-up steps this procedure is both time consuming and prone to side reactions that promote discrimination of single constituents, especially when no peralkylation step is performed prior to hydrolysis. As a consequence results scatter in dependence on individual treatment and conditions. In the context of this work these critical points were overcome by strict but simplified work-up procedures and using acid instead of alkaline catalyzed acetylation. Under the acidic conditions the tedious removal of borate is no longer necessary and a reduced time requirement was achieved as well as good reproducibility. Comparison with independent reference methods excluded a systematic error of the method and confirmed the results obtained. Without peralkylation, i.e. in the presence of free hydroxyl groups, another fast modification of the method using DMSO as solvent, no removal of borate, and 1-methylimidazole as catalyst for acetylation was found to produce a systematic error.

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“…Optimization of the methylation conditions could avoid this side-reaction. [63] Due to the strongly enhanced acid lability of glucosyl linkages in 2-sulfates reductive hydrolysis that was introduced by Lindberg [64] was applied as described by Stevenson and Furneaux [65] to stabilize early liberated glucose residues by direct reduction to glucitols. After complete hydrolysis, reduction and acetylation again the partially methylated glucitol acetates are obtained.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

“…The methylated product is directly isolated via Sephadex LH 20 chromatography with methanol as the eluent. [63] Permethylation of glucan acetates and trialkylsilyl ethers of 1,4-a-glucans: Permethylation is performed according to Prehm [57] with methyl triflate/2,6-di-tert-butylpyridine in trimethyl phosphate [59] or with trimethyl oxonium tetrafluorobo- Fig. 6.…”

Section: Experimental Partmentioning

confidence: 99%

“…[23] This procedure can be modified according to Horner et al [27,76] For sulfates the reductive hydrolysis method of Garegg et al [64] as described by Stevenson and Furneaux [65] was applied to prevent losses of early liberated glucose-2-sulfates. [63] Methanolysis: The permethylated sample (1 -2 mg) in a 1 mL V-vial is treated with 1.5 M methanolic HCl at 100 8C for 2 h. The solvent is removed in a stream of nitrogen. Methanolysis can be applied prior to acid hydrolysis to hydrophobic trialkyl silyl ethers in a two-step procedure.…”

Section: Experimental Partmentioning

confidence: 99%

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Structure analysis of 1,4-glucan derivatives

Mischnick

Heinrich

Gohdes

et al. 2000

Macromol. Chem. Phys.

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Cellulose, starch and cyclodextrin ethers and esters are produced for many fields of application as for example oil recovery, building and ceramic materials, textile and paper industry, food, cosmetics, and pharmaceuticals. For further development of new types of derivatives and also for a better understanding of their properties a detailed analysis of the usually complex mixtures is required. By complete degradation, separation and quantification of appropriate monomer derivatives the regioselectivity in the glucose unit can be determined. For the determination of the substitution pattern in the polymer chain partial random degradation, oligomer analysis by mass spectrometry, and subsequent statistical evaluation can be applied. The composition of products obtained by enzymatic degradation also reflects the pattern in the polymer chain. In addition a possible heterogeneity of the material must be taken into consideration, since any degradation averages the structural information.

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Methylation analysis of cellulose sulphates

Cited by 21 publications

References 19 publications

Inhibition of Chondroitin-4-Sulfate-Specific Adhesion of Plasmodium falciparum -Infected Erythrocytes by Sulfated Polysaccharides

Inhibition of Chondroitin-4-Sulfate-Specific Adhesion of Plasmodium falciparum -Infected Erythrocytes by Sulfated Polysaccharides

Critical re-investigation of the alditol acetate method for analysis of substituent distribution in methyl cellulose

Structure analysis of 1,4-glucan derivatives

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