Interaction of amylose and other α-glucans with hydrophobic fluorescent probe (2-p-toluidinylnaphthalene-6-sulfonate)

✍ Scribed by Hiroshi Nakatani; Ken-Ichiro Shibata; Hitoshi Kondo; Keitaro Hiromi

• Publisher: Wiley (John Wiley & Sons)
• Year: 1977
• Tongue: English
• Weight: 376 KB
• Volume: 16
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1977.360161103

✦ Synopsis

Fluorescence of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) was enhanced in the presence of maltooligosaccharides, amylose, and other a-glucans. The dependence of relative TNS fluorescence intensity per glucose unit on chain length of oligosaccharides was examined. The values of binding constant and thermodynamic parameters, assuming the 1: 1 complex for TNS-amylose (number-average degree of polymerization, DP, = 17), were determined by the fluorescence titration. The values of thermodynamic parameters for 1:l complex formation of TNS-a-and P-cyclodextrins were also determined and compared with those of TNS-amylose (DP, = 17). The fluorescence intensity of TNS in the presence of amylose (DP, = 600) decreased by the action of glucoamylase and taka-amylase A. The fluorescence of TNS-amylose (DP, = 17) system increased with the increased ionic strength. In the presence of pullulan, T N S fluorescence was also enhanced and decreased by the action of pullulanase. Amylopectin enhanced T N S fluorescence rather more strongly than amylose (DP, = 17) at the same concentration. In the presence of dextran, the fluorescence of TNS was scarcely enhanced. The degree of fluorescence enhancement of TNS in the presence of a-glucans seems to reflect the structures of a-glucans in solution, since T N S fluorescence is enhanced in the hydrophobic environment or by the disturbance of free intramolecular rotation.