Complex carbohydrates glycoproteins

Figure 13-10. Glucosamine (2-amino-D-glucopyra-nose) a form). Galactosamine is 2-amino-D-galactopy-ranose. Both glucosamine and galactosamine occur as N-acetyl derivatives in more complex carbohydrates, eg, glycoproteins.

A feasible way of introducing acid-stable linkages into carbohydrates is N-deacetylation. This can be achieved with hydrazine.59,70,71 The use of sodium hydroxide-sodium benzenethioxide in aqueous dimethyl sulfoxide for this purpose has also been described72 The difference in the acid hydrolysis of N-acetylhexosamine-con-taining carbohydrates before and after N-deacetylation was used in the study of complex glycoprotein saccharides from human erythrocyte membranes.73-75 Methylation analysis of the glycopeptides prepared... 

Sugar moieties on glycoproteins Protein-carbohydrate complexes identification and mimicking of key residues determining monosaccharide specificity Solid-phase combinatorial chemistry (80 ligands) Affinity chromatography 1H-NMR studies 8,16,17... 

Analysis of Proteins and Complex Carbohydrates from Glycoproteins... 

Several aspects of neutron scattering studies are particularly elegant and unique in terms of the contrast variation method to examine internal structures as well as the external morphology. Thus the protein positions within the 30S ribosomal subunit can be determined by triangulation of deuterated subunits [489,490] the shell-like spherical structures of protein, lipid and nucleic acid within viruses [546,555,566] and lipoproteins can be analysed the distinct disposition of carbohydrates within glycoproteins [197,198,214], membranes within membrane proteins [39], or proteins within protein-nucleic acid complexes [385,387,392] can be elucidated. Likewise X-ray scattering has been of value in protein-lipid systems since these two components can be readily distinguished from one another [75,76]... 

Methods have been reported for the ultrastructural localization of complex carbohydrates, including glycoproteins, in rat macrophages and monocytes, by employing the reactivity of vicinal glycols to periodate ions and the presence of carboxy- and sulphate ester-groups. ... 

Bush CA, Martin-Pastor M, and Imberty A (1999) Structure and conformation of complex carbohydrates of glycoproteins, glycohpids, and bacterial polysaccharides. Annual Review of Biophysics and Biomolecular Structure 28 269-293. 

Natural hCG. hCG is a particularly complex glycoprotein in that 25-30% of its molecular weight is composed of carbohydrates up to 35-41% in hyperglycosylated hCG. 

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