Neoglycoproteins reactions

In the preparation of affinity adsorbents, it is necessary to attach the ligand residues to insoluble supports by chemical bonds or physical interactions. Adsorbents having carbohydrate ligands have been prepared for the most part by chemical reaction of carbohydrate derivatives with the support material. Methods for the preparation of some types of carbohydrate derivatives are described in Section IV. Methods for the preparation of other derivatives of carbohydrates that may be suitable for synthesizing affinity adsorbents have been described in an article on neoglycoproteins.31... 

The choice of the modification reaction will be determined by the nature of the carbohydrate to be attached, as well as by the nature of the protein. The intended uses to which the neoglycoprotein will be put may also determine the suitability of a particular approach. The procedures described are varied, and offer a number of options for the preparation of neoglycoproteins. 

A transglutaminase reaction was found to be useful in the preparation of neoglycoproteins. For example, oo-amino glycosides were used as a substrate for transglutaminase for the addition of carbohydrates to glutamine side chains (35, 36). The success of this reaction, however, seems somewhat unpredictable. 

The advantage of glycamine over glycosylamine is that the former is more stable during the amidation reaction to form neoglycoproteins, typically using water soluble carbodiimide at pH 4-5. Glycamines have also been used to modify poly-carboxylic compounds, such as poly-Asp or poly-Glu [26,28]. 

How can these units be bound to polymeric carriers The majority of data reported in the literature relating to sugar binding reactions concerns the modification of proteins (with the formation of the so-called neoglycoproteins). The binding reactions for the modification of proteins can also be applied to synthetic polymers and they are briefly outlined below. 

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