Affinity-chromatography Matrices as Derivatives of Polysaccharides

Affinity chromatography is similar in principle to the use of immuno-adsorbents for antibody and antigen purification (see Section IX, p. 375) and of insolubilized nucleic acids for purification of nucleic acids and related enzymes (see Section X, p. 384). The subject of affinity chromatography in general has been reviewed, ° and a mechanism 

However, one of the first matrices used for insolubilization of the aflBnant was cellulose that had been partially etherified with 3-hydroxy-phenoxy or 4-diazobenzyl groups (which react with diazotized protein or protein, respectively). Amino compounds may also be attached to the acid chlorides of carboxy polysaccharides.0-(3-Allyloxy-2-hydroxy-propyl)-cellulose and -Sephadex can be mercuriated and, in this form, used for isolation of thiolated antibodies and fractionation of mononucleotides according to their aflBnity for an organomercurial. Another mercurial, prepared by treatment of 0-(2-aminoethyl)Sephadex with IV-acetylhomocysteine thiolactone to give a thiol (49) which, on treatment with 2,5-bis[(acetoxymercuri) methyl]-1,4-dioxane, gives 50, can also be used in aflSnity chromatography of thiolated proteins. 

Macromolecular affinants can be insolubilized in different modes of attachment by virtue of their several functional groups. Furthermore, some degree of selectivity in the point of linkage can be achieved where 

0-(2-Diethylaminoethyl)cellulose amino acid derivatives 652a 

One type of affinity-chromatography material of particular interest in carbohydrate chemistry is the insolubilized derivative of concanavalin A, a phytohemagglutin that shows specificity towards certain carbohydrates. 

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