title: Fluorescent studies on cooperative binding of cationic pheophorbide-a derivative to polyphosphate.
abstract: 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.
authors.affiliation: B. Verkin Institute for Low Temperature Physics and Engineering of NAS of Ukraine, Department of Molecular Biophysics, Kharkov, Ukraine. ryazanova@ilt.kharkov.ua
authors.forename: Olga
authors.initials: O
authors.lastname: Ryazanova
authors.forename: Igor
authors.initials: I
authors.lastname: Voloshin
authors.forename: Igor
authors.initials: I
authors.lastname: Dubey
authors.forename: Larisa
authors.initials: L
authors.lastname: Dubey
authors.forename: Victor
authors.initials: V
authors.lastname: Zozulya
mesh_terms: D000042:Absorption; D002412:Cations; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000737:chemistry; D019281:Dimerization; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence / Q000379:methods*; D008956:Models, Chemical; D010777:Photochemistry / Q000379:methods; D011108:Polymers / Q000737:chemistry; D011122:Polyphosphates / Q000737:chemistry*; D012995:Solubility; D055672:Static Electricity
chemical_list: D002412:Cations; D005456:Fluorescent Dyes; D011108:Polymers; D011122:Polyphosphates; D002734:Chlorophyll; C032623:pheophorbide a