Oligosaccharides enzymic method

Full interpretation of data of this type must await further understanding of the specificities of the enzymes involved, of the nature of the residual oligosaccharide, and of the problem of possible heterogeneity discussed earlier. An advantage of enzymic methods is that the anomeric configuration may be revealed. 

The development of chemical, physical, and enzymic methods for investigating the primary structure of the carbohydrate fractions of glycoconjugates has, during the past ten years, allowed the determination of the structures of numerous glycans. In this regard, the combination of the techniques of permethylation and 360-MHz, proton-n.m.r. spectroscopy has afforded real progress in the rapid determination of the primary structures of oligosaccharide chains. 

We have already approached the synthetic problems relative to these oligosaccharides. Concerning glycosylamines, we have given the preparation of glucosides of asparagine in Section 3.6.2 and, as a synthetic example using enzymic methods, the synthesis of a peripheral sequence, 12.21. 

The tridecacompound 33, which contains two siaLe tetrasaccharide units was put together relatively readily by enzymic methods. The reducing end of the initial oligosaccharide required for the synthesis was linked to asparagine. ... 

In order to investigate, and deduce, the complex carbohydrate structures of glycoproteins, it must be possible to release, and isolate, the oligosaccharide chain(s) from the glycoprotein. Following this, the structure is usually deduced by a combination of enzymic, chemical, and instrumental methods.34-36... 

The challenge for developing methods for synthesizing oligosaccharides, notably for complex oligosaccharides, that can be scaled up to an industrial level is obvious, based on the use of substrates and enzymes that are available at reasonable cost and purity. Strategies for oligosaccharides synthesis include ... 

Glycal assembly on a solid support eliminates the repetitive purifications usually associated with oligosaccharide synthesis. As a method, it has a certain generality as it does not require any specific enzymes or complex starting materials. Both natural and nonnatural sugars may be used in the constructions. 

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