Blue Dextran 2000, structure

Fig. 20. Structured flows developed between the bottom solution containing dextran with 6.146 x 10-2 g/g phosphate buffer at pH 6.0 and dextranase with 10 units/g phosphate buffer (= 2.63 x 10s g/g phosphate buffer) and the top solution containing dextran with 3.952 x 10-2 g/g phosphate buffer (including blue dextran). The boundary was formed 3 min after the dextranase was added to the dextran solution. The photo was taken 30 min after formation of the initial boundary531...

Kapoor, M. O Brien, M.D. Studies of the structure-function relationships of Neurospora crassa pyruvate kinase interaction with blue dextran-se-pharose and Cibacron blue 3G-A. Can. J. Microbiol., 26, 613-621 (1980)... 

The structure of Blue Dextran 2000, a water-soluble commercial derivative, involves a triazine type of dye covalently linked to dextran, and, in a way analogous to that used for other dyed polysaccharides, has been employed for the assay of dextranase. The ability of Blue Dextran 2000 to bind proteins cannot be attributed to formation of a covalent link, because no chloro groups remain on the triazinyl rings. The binding must involve an ionic bond between the protein and the sulfonic groups of the dye residue, and, in one case, the association could be reversed by using 0-(2-diethylaminoethyl) cellulose to abstract the dyed polysaccharide. Other chlorotriazinyl dyes have been used in the preparation of dyed derivatives of amylopectin, laminaran, dextrans, pectin, pelvetian, zosterine, and cellulose. As already mentioned, triazine-dyed polysaccharides are useful in enzyme insolubilization. 

Fig. 19. Time-dependent development of structured flows in a dextran/sorbitol system (see legend of (Fig. 18) with blue-labelled dextran initially introduced into the bottom solution. The photograph was taken 2 h after formation of the boundary layer...

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