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Interaction of amylose and other α‐glucans with hydrophobic fluorescent probe (2‐ p ‐toluidinylnaphthalene‐6‐sulfonate)
Author(s) -
Nakatani Hiroshi,
Shibata KenIchiro,
Kondo Hitoshi,
Hiromi Keitaro
Publication year - 1977
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1977.360161103
Subject(s) - chemistry , amylose , fluorescence , amylopectin , degree of polymerization , titration , ionic strength , fluorescence anisotropy , fluorescence spectroscopy , glucan , photochemistry , polymerization , starch , inorganic chemistry , organic chemistry , aqueous solution , biochemistry , polymer , physics , quantum mechanics , membrane
Fluorescence of 2‐ p ‐toluidinylnaphthalene‐6‐sulfonate (TNS) was enhanced in the presence of maltooligosaccharides, amylose, and other α‐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 N = 17), were determined by the fluorescence titration. The values of thermodynamic parameters for 1:1 complex formation of TNS‐α‐ and β‐cyclodextrins were also determined and compared with those of TNS‐amylose ( DP N = 17). The fluorescence intensity of TNS in the presence of amylose ( DP N = 600) decreased by the action of glucoamylase and taka‐amylase A. The fluorescence of TNS‐amylose ( DP N = 17) system increased with the increased ionic strength. In the presence of pullulan, TNS fluorescence was also enhanced and decreased by the action of pullulanase. Amylopectin enhanced TNS fluorescence rather more strongly than amylose ( DP N = 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 α‐glucans seems to reflect the structures of α‐glucans in solution, since TNS fluorescence is enhanced in the hydrophobic environment or by the disturbance of free intramolecular rotation.