Carbohydrates, estimation

S. Kilz, H. Budzikiewicz, and S. Waffenschmidt, In-gel deglycosylation of sodiumdodecyl sulfate polyacrylamide gel electrophoresis-separated glycoproteins for carbohydrate estimation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, J. Mass Spect-rom., 37 (2002) 331-335. 

The degree of glycosylation of the glycopolypeptides was estimated via H NMR, MALDI-TOF, and periodate assay (Glycoprotein Carbohydrate Estimation Kit (Pierce, Rockford, IL). H NMR spectra were acquired on a Bruker DRX-400 NMR spectrometer under standard quantitative conditions at 25 °C, and the standard protocols for the periodate assay were as described by the manufacturer. Comparison of sample solutions to a calibration curve of proteins of known carbohydrate content, combined with quantitative amino acid analysis of the samples, permitted estimation of the degree of substitution of the glycopolypeptides. 

PL-Beta was assumed to consist of pure xylan and the spectrum was subtracted form all other spectra for carbohydrate estimation... 

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 aromatic nature of lignin contrasts with the aliphatic stmcture of the carbohydrates and permits the selective use of electrophilic substitution reactions, eg, chlorination, sulfonation, or nitration. A portion of the phenoUc hydroxyl units, which are estimated to comprise 30 wt % of softwood lignin, are unsubstituted. In alkaline systems the ionized hydroxyl group is highly susceptible to oxidative reactions. 

It has been estimated that >90% of the carbohydrate mass in nature is in the form of polysaccharides. In living organisms, carbohydrates play important roles. In terms of mass, the greatest amounts by far are stmctural components and food reserve materials, in that order and both in plants. However, carbohydrate molecules also serve as stmctural and energy storage substances in animals and serve a variety of other essential roles in both plants and animals. 

Regarding the total amount of assimilated biomass, carbohydrates/polysaccha-rides represent the dominant class with an estimated amount of 1-4 X 10" tons of dry matter produced by photosynthesis annually ... 

Energy values of food can be estimated on the basis of the content of carbohydrate, protein, and fat ... 

This is the only function of maltase, but it is one that no other enzyme can perform. Many such digestive enzymes are required for the metabolism of carbohydrates, proteins, and fats. It has been estimated that without enzymes, it would take upward of 50 years to digest a meal. 

Po and rio are the densities and viscosities of the solvent, P2o,w and rj2o,w the corresponding values at 20.0 °C in water, v is the partial specific volume, which for neutral polysaccharides can often be reasonably estimated from the carbohydrate content [31] and takes on values between 0.5-0.7 ml/g for... 

The significance of n.m.r. spectroscopy for structural elucidation of carbohydrates can scarcely be underestimated, and the field has become vast with ramifications of specialized techniques. Although chemical shifts and spin couplings of individual nuclei constitute the primary data for most n.m.r.-spectral analyses, other n.m.r. parameters may provide important additional data. P. Dais and A. S. Perlin (Montreal) here discuss the measurement of proton spin-lattice relaxation rates. The authors present the basic theory concerning spin-lattice relaxation, explain how reliable data may be determined, and demonstrate how these rates can be correlated with stereospecific dependencies, especially regarding the estimation of interproton distances and the implications of these values in the interpretation of sugar conformations. 

Uronic acid was estimated by the rw-hydroxyphenyl method [4], O-Acetyl contents by the method of Hestrin [5], carbohydrate by the phenol-sulfuric acid method [6] and protein by the Hartree method [7]. 

Determination of neutral carbohydrate Total neutral carbohydrate in protein samples was estimated by the phenol/sulphuric acid method of Dubois [13] using mannose as standard. 

It is experimentally difficult to obtain numerical estimates of the total number of bacteria present in seawater, and the contribution of ultramicroorganisms that have a small cell volume and low concentrations of DNA may be seriously underestimated. Although it is possible to evaluate their contribution to the uptake and mineralization of readily degraded compounds such as amino acids and carbohydrates, it is more difficult to estimate then-potential for degrading xenobiotics at realistic concentrations. 

In all cases where the chemical properties of these preparations have been studied the active material appears to be predominantly carbohydrate in nature, containing in the case of the A factor 50-70% of reducing sugar, 5.7% nitrogen and giving by colorimetric estimations 25-30% of glucosamine on hydrolysis. 

Sorensen and Haugaard147 showed that by a suitable fractionation of crystalline albumin there could be obtained a series of fractions which, although crystalline, varied widely in their properties, particularly in regard to their carbohydrate contents. The most soluble fraction contained about fifty times as much carbohydrate as the least soluble. In most of these studies the carbohydrates were estimated by modification of the orcinol colorimetric method of Tillmans and Philipi181 which could... 

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