Monosaccharide Determination

The analysis of monosaccharide mixtures as the permethylated derivatives was proposed early in the application of gas-liquid chromatography to carbohydrates, but the method has now been superseded by more convenient procedures.230,231 There are, however, situations in which this method is useful, such as during a structural study of a polysaccharide by the methylation technique. The mixture of partially methylated monosaccharides obtained by methanolysis may then be fully methylated, and the proportions of the various monosaccharides determined. This approach has been used, for example, in studies on a galactomannan392 and on tamarind-kernel polysaccharide.393 Such an analysis also constitutes a useful check to ensure that no significant change in the composition of the polysaccharide occurred during methylation. 

The set of variously iV-acylated 2,3-unsaturated sialic acids 70 was synthesized to probe the activity of the sialidase of Vibrio cholerae, the causative agent of cholera. Syntheses of a range of fluorinated analogues of the methyl glycoside of 4-(2,4-dihydroxybutryoyl)amino-2,6-dideoxy-D-mannopyranose, the monosaccharide determinant of Vibrio cholerae are covered in Chapter 8. 

The results established the propensity for stabilizing cooperative structures through multiple hydration and led to a generalization of the mles for conformational selectivity in hydrated monosaccharides [51, 52]. The preference of water molecules for cooperatively bonded conformations of the monosaccharide is such that it can promote conformations which are not favored for the isolated molecule. This is illustrated in the case of the different anomeric forms of Man-O-Ph in Fig. 4b, where the conformations of the isolated and sequentially hydrated monosaccharide, determined from the interpretation of gas-phase IRID spectra, are shown. The a anomer adopts a preferred cG-g+ cooperative conformation. It is unaffected by micro-hydration as water molecules can insert at different sites to increase the cooperative strengthening of the H-bond network. In the p anomer, the equatorial position of 01 turns on the OH2 —> 01 interaction and the preferred... 

Lid6n H, Vole J, Marko-Varga G, Gorton L. Pyranose oxidase modified carbon paste electrodes for monosaccharide determination. Electroanalysis 1998 10 223-230. 

Identify the products of oxidation or reduction of monosaccharides determine whether a carbohydrate is a reducing sugar. 

Of all the monosaccharides d (+) glucose is the best known most important and most abundant Its formation from carbon dioxide water and sunlight is the central theme of photosynthesis Carbohydrate formation by photosynthesis is estimated to be on the order of 10 tons per year a source of stored energy utilized directly or indi rectly by all higher forms of life on the planet Glucose was isolated from raisins m 1747 and by hydrolysis of starch m 1811 Its structure was determined in work culmi nating m 1900 by Emil Fischer... 

The monosaccharide composition of all the samples was determined by GLC analysis of the trimethylsilyl methyl glycoside derivatives [1]. 

The anomeric configurations of the sugar residues were determined by chromium trioxide oxidation [14], Oxidation of the fully acetylated polysaccharide and subsequent monosaccharide analysis by GLC indicated that the D-Xyl units are P-linked (oxidized more rapidly) and that die D-GlcA are a-linked (Table II). 

Rha, Ara and Gal are the neutral sugar components from all the fractions. Xyl is not present in Fla and is significantly present in the hemicellulose fractions, indicating that this monosaccharide is component of hemicellulosic polymers. Chemical composition of the water fractions were determined (Table V). High protein contents and the presence of O-acetyl-groups were observed in four aqueous fractions. Neutral sugar and uronic acid composition points to inclusion of these polymers in the class of pectic polysaccharides. 

The concentration of cell wall monosaccharides was analyzed by gas chromatography (4). Determination of total and free acids was performed according to Ehwald et al. (5). Cell wall size exclusion limits were measured as decribed by Ehwald et al. (6). 

The content of neutral monosaccharides was determined after an acid hydrolysis, performed as follows with 72 % sulphuric acid for 1 hr at 30°C and then, after dilution to IM sulphuric acid, for another 3 hr s at 100°C. The determination was performed by GC analysis of the prepared alditol acetates (13,14)... 

The content of galacturonic acid in the fractions, obtained by gel chromatography, was determined by the carbazole method (9), and the content of neutral monosaccharides was determined by the anthron reaction (16). 

Pastore, P., Lavagnini, I., and Versini, G., Ion chromatographic determination of monosaccharides from trace amounts of glycosides isolated from grape musts, /. Chromatogr., 634, 47, 1993. 

Tomiya, N., Suzuki, T., Awaya, J., Mizuno, K., Matsubara, A., Nakano, K., and Kurono, M., Determination of monosaccharides and sugar alcohols in tissues from diabetic rats by high-performance liquid chromatography with pulsed amperometric detection, Anal. Biochem., 206, 98, 1992. 

Sabbagh, N. K., Faria, J. B., Yokomizo, Y., Determination of monosaccharides in soluble Brazilian coffees, Col. Inst. Technol. Aliment. (Campinas, Braz.), 8, 55, 1977. (CA89 89059j)... 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

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