Oligosaccharide utilization

N-Linked Oligosaccharides Utilize a Lipid Carrier in the Early Stages of Synthesis... 

A detailed inspection of the coupling constants 3J5 6, and 3 J5 6 of several manno-sidic oligosaccharides utilizing phase sensitive COSY spectra has been reported [29]. The population analysis based on these coupling constants shows the preference of the gg conformation over gt while tg is not found within the precision of the analysis. 

Usui, T., Matsui, H., and Isobe, K. 1990. Enzymic synthesis of useful chito-oligosaccharides utilizing transglycosylation by chitinolytic enzymes in a buffer containing ammonium sulfate. Carbohydr. Res. 203 65-77. 

Coenzymes serve as recyclable shuttles—or group transfer reagents—that transport many substrates from their point of generation to their point of utilization. Association with the coenzyme also stabilizes substrates such as hydrogen atoms or hydride ions that are unstable in the aqueous environment of the cell. Other chemical moieties transported by coenzymes include methyl groups (folates), acyl groups (coenzyme A), and oligosaccharides (dolichol). 

Scheme 5.25 First utilization of an NPOE in oligosaccharide synthesis.

The presence of flexibility and motion in oligosaccharides, as in the case of proteins or nucleic acids, complicates the utilization of dipolar coupling data in structure refinement. Dipolar couplings are averaged because of conformational flexibility, but it is also possible that the various existing conformations orient differently with respect to the magnetic field. 

The utilization of whole cells as bioreactors for the synthesis of oligosaccharides and engineering cell lines for the production of glycoproteins with a human-Hke glycosylation pattern are highlights in the field of glycobiotechnology. 

In summary, different strategies for the combinatorial biosynthesis of oHgosaccharides have been established successfully. However, some systems are Hmited mostly to bacterial glycosyltransferases because of their better expression in E. coli. The yeast systems seem to be better suited for expression of mammahan glycosyltransferases however, it remains to be demonstrated if they can be also utilized as living factories for the production of oligosaccharides. 

The most frequently used CSPs for biological applications in the reversed-phase mode are based on macrocyclic antibiotics, proteins, or oligosaccharides, but some of the applications utilize phases based on polysaccharides, low-molecular-weight selectors, crown ethers, or columns based on immunoaffinity techniques (Table 17.5). 

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