Introduction carbohydrates

Anomeric carbon (17.5) Anomers (17.5) Biochemistry (Introduction) Biomolecule (Introduction) Carbohydrate (17.1)... 

For mixture.s the picture is different. Unless the mixture is to be examined by MS/MS methods, usually it will be necessary to separate it into its individual components. This separation is most often done by gas or liquid chromatography. In the latter, small quantities of emerging mixture components dissolved in elution solvent would be laborious to deal with if each component had to be first isolated by evaporation of solvent before its introduction into the mass spectrometer. In such circumstances, the direct introduction, removal of solvent, and ionization provided by electrospray is a boon and puts LC/MS on a level with GC/MS for mixture analysis. Further, GC is normally concerned with volatile, relatively low-molecular-weight compounds and is of little or no use for the many polar, water soluble, high-molecular-mass substances such as the peptides, proteins, carbohydrates, nucleotides, and similar substances found in biological systems. LC/MS with an electrospray interface is frequently used in biochemical research and medical analysis. 

All chemical information not involving carbohydrates, but nevertheless necessary to the understanding of this chapter, is gathered in this Introduction, and is found in the following subsections. 

As mentioned in the Introduction, a variety of unusual carbohydrate -protein linkages is found in Nature. These may be placed in several categories (i) carbohydrates O-glycosylated to jff-hydroxy amino acids (ii) carbohydrates S-glycosylated to cysteine (Hi) carbohydrates N-gly-cosylated to the N-terminal amino group of the protein or (iv) in some... 

The introduction of electronic asymmetry into this class of bis(diaryl)phosphinites has been used to design catalysts that can afford both enantiomers of naproxen nitrile. If the carbohydrate scaffold is based on methyl o-D-fructol uranosidc (29), (i )-naproxen nitrile is produced. In a similar manner to the results above, electron-donating aryl substituents on phosphorus afford... 

The growing interest for the identification and characterization of polar and large compounds caused the development and the introduction of new ionization techniques, such as electrospray ionization (ESI)[4], and matrix assisted laser desorption ionization (MALDI),[5] and their more recent improvements, thus establishing new MS based approaches for studying large molecules, polymers and biopolymers, such as proteins, carbohydrates, nucleic acids. 

M. Wilstermann and G. Magnusson, Synthesis of disaccharide glycosyl donors suitable for introduction of the /i-D-Galp-0 >3)-a- and -jS-D-GalpNAc groups, Carbohydr. Res., 272 (1995) 1-7. 

K. Buchholz, Introduction The spirit of carbohydrates—Carbohydrate bioengineering, Biocatal. Biotransformation, 26 (2008) 3-11. 

Alternative strategies utilizing the initial introduction of suitable chemical functionality onto the fullerene have been adopted by several research groups, allowing conjugation of the saccharides with complementary functions in the final synthetic steps. This approach has led to improved flexibility with the chemical functions on the carbohydrate moieties, especially the anchoring ones, and a better control on the number of attached saccharide residues. 

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