Induced optical activity of chondroitin sulfate c–acridine orange complexes

Chondroitin sulfate C (CSC) and acrdiine orange (AO) formed two types of complexes at neutral pH, depending upon the order of mixing. The induced optical activity of AO was much more pronounced when the polysaccharide was added to dye than the dye to polymer (final concentration of dye was 5 × 10⁵M). The difference in aggregation of the dye molecules is believed to be responsible for the observed peculiarities. The Cotton effects of the CSC-to-dye solution displayed a sharp inversion near 59°C. and the profile at 76°C. was almost a mirror image of that at room temperature. At pH 1.3, however, the order of mixing became unimportant, suggesting that the carboxylate on the polysaccharide way involved more intimately than were sulfates in the peculiarities of the Cotton effects.