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Fluorescent Studies on Cooperative Binding of Cationic Pheophorbide‐a Derivative to Polyphosphate
Author(s) -
Ryazanova Olga,
Voloshin Igor,
Dubey Igor,
Dubey Larisa,
Zozulya Victor
Publication year - 2008
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1430.033
Subject(s) - pheophorbide a , fluorescence , polyphosphate , chemistry , cationic polymerization , derivative (finance) , titration , dimer , quenching (fluorescence) , aqueous solution , fluorescence spectroscopy , photochemistry , cooperative binding , phosphate , binding site , inorganic chemistry , organic chemistry , biochemistry , photodynamic therapy , physics , quantum mechanics , financial economics , economics
The cooperative binding of a novel water‐soluble cationic derivative of pheophorbide‐ a (CatPheo‐ a ) to inorganic polyphosphate (PPS) in buffered aqueous solutions was studied by means of polarized fluorescence spectroscopy in a wide range of molar phosphate‐to‐dye ratios (P/D). Under low P/D values, CatPheo‐ a forms extended stacking associates on the PPS matrix, while under high P/D the dye binds to PPS in the dimer form. The CatPheo‐ a self‐association is accompanied by 40‐fold dye fluorescence quenching and a substantial increase in the fluorescence polarization degree. The fluorescent titration data were used for determination of cooperative binding parameters by Schwarz's method.