Labeled Sugars

C -labeled sugars have been prepared both by biosynthetic and synthetic methods (Chapter II). P. j beled sugar phosphates have also been produced biosynthetically (22). Biosynthetically produced C -labeled sugars are of limited value because of the distribution of label between the various carbon atoms. The 3,4-C Mabeled glucose isolated from liver glycogen (41) is an exception. 

A chemical method (41) of degrading glucose was developed to distinguish between carbon atoms 3 and 6. D-Glucose was converted to the methyl D-glucopyranoside which was then oxidized with periodic acid at room temperature to convert carbon atom 3 to formic acid. A second periodic acid oxidation of the hydrolyzed dialdehyde, which was also produced, gave carbon atom 6 as formaldehyde. 

Aronoff and Vernon (42) converted glucose to the glucosazone which was then degraded with periodate. This oxidation gave the bis(phenyl- 

The ethanol and lactic acid can be degraded by conventional chemical methods to give the distribution of label in each of the carbon atoms of D-glucose. 

Methods for degrading ribulose (n-er / Aro-pentulose) and sedoheptulose (n-aZ ro-heptulose) have been devised by Bassham and associates 46). Biological methods of degradation depending on the action of bacteria to produce small fragments such as ethanol, acetic acid, formic acid, lactic acid, etc., are of rather wide use in the sugar field. 

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The general approach has been followed for the de novo synthesis of a multitude of differently substituted, unsaturated [112,113] or regiospedfically labeled sugars [102,114]. Unusual branched-chain (42), (43)) and spiro-annulated sugars (45), (46)) have been synthesized from the corresponding aldehyde precursors... 

In addition to the foregoing examples, periodate oxidation has been applied to isotopically labeled sugars (for the determination of label distribution), 226 -226 to certain branched-chain sugars,227-229 and to some nitrogenous derivatives of the simple sugars.230-236... 

Ekblad A, Nyberg G, Hogberg P (2002) 13C-discrimination during microbial respiration of added C3-, C4- and 13C-labelled sugars to a C3-forest soil. Oecologia 131 245-249... 

A sequence known as the Kiliani-Fischer synthesis was developed primarily for extending an aldose chain by one carbon, and was one way in which configurational relationships between different sugars could be established. A major application of this sequence nowadays is to employ it for the synthesis of " C-labelled sugars, which in turn may be used to explore the role of sugars in metabolic reactions. 

An ultraviolet (UV) monitor is most commonly used in CE experiment. Such interaction studies using the ACE method can also be hampered by the inadequate sensitivity of UV detection. Fluorescence labeling and laser-induced fluorescence (LIF) detection have been employed to enhance the sensitivity of this method, as shown by the mobility-shift assay of fluorescence-labeled sugar caused by the interaction with the lectin, concanavalin A (74). When fluorescent dyes are employed for labeling, LIF detection provides several hundred times more sensitivity than UV detection. 

In a study using 14C-labelled sugars, it was shown that the recovery of trimethylsilyl derivatives was approximately 25%, whereas only... 

The recovery of trimethylsilyl and trifluoroacetyl derivatives has been examined by use of 14C-labelled sugars, and it has been shown that glucose trifluoroacetate is recovered208 to the extent of 3 to 5% on SF-96, or of 5 to 14% on Carbowax 20 M. 

To broaden the scope of his interests, he spent another year as a postdoctoral fellow in the Physics Department of Pennsylvania State University, working on the X-ray analysis of biological compounds. Equipped with an exceptionally broad and multidisciplinary education and experience, he proceeded to The Ohio State University, Columbus, Ohio, to work with Professor M. L. Wolfrom. His initial job was to investigate the ignition of cellulose nitrate, a project left over from World War II. In Fred s hands, this project was turned into an isotopic investigation of the biosynthesis and degradation of cellulose. At this time, there was very little known about the preparation of specifically labeled sugars, let alone the biosynthesis of... 

On the other hand, the use of specifically l3C-labelled sugars, developed by Barker and Serianni,5-13 has been applied to many sugars it is particularly useful when the label is in position 1. Labelling results in an 100-fold increase of the l3C signal of the labelled carbon atom, making it possible to detect components occurring in very small proportions, down to 0.01% for example, for ribose10 at 25°, —0.05% of free aldehyde. These results are discussed in Sections III,4 and III,5. 

V. H. Kollman, J. L. Hanners, J. Y. Hutson, T. W. Whaley, D. G. Ott, and C. T. Gregg, Large scale photosynthetic production of carbon-13 labeled sugars The tobacco leaf system, Biochem. Biophys. Res. Comm., 50 (1973) 826-831. 

The action of lead tetraacetate on osazones of Cw-labeled sugars in warm aqueous acetic acid has been employed46 for determining specific activity of the oxidizable carbon atoms present, that is, C4, C5, and C6 of D-glucose phenylosotriazole. In the potassium acetate-catalyzed oxidation, D-glucos-azone (o-arabino-hexose phenylosazone) yielded two moles of formic acid... 

CZE separation of sugar isomers in a PMMA chip was enhanced by using a phosphate-based, rather than a borate-based buffer. The resolution enhancement may be caused by a rapid carbohydrate-phosphate complex formation process, as compared to a slow carbohydrate-borate complex formation process. To reduce adsorption of the labeled sugar isomers to the PMMA surface, 0.5% methylcel-lulose (viscosity of 2% aqueous solution at 20°C, 4000 cP) was added to the run buffer [560],... 

R. Tressl, E. Kersten, C. Nittka, and D. Rewicki, Formation of sulfur-containing flavor compounds from [13C]-labeled sugars, cysteine, and methionine, in Sulfur Compounds in Foods, C. J. Mussinan and M. E. Keelan (eds), American Chemical Society, Washington, DC, 1994, 224-235. 

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