Emiko Okamura - Binding of Hydrophobic Fluorinated Bisphenol A to Large Unilamellar Vesicles of Egg Phosphatidylcholine

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      Publication Details (including relevant citation   information):

         N. Yoshii,E. Okamura, J. Phys. Chem. B, 115, 11074-11080   (2011).    


      The kinetics of   membrane binding and dissociation of fluorinated  bisphenol A   (FBPA,  (CF3)2C(C6H4OH)2)   is quantified by one-dimensional   (1D)19F  NMR   spectra in   situ.  Although  the bound and   free components are in fast exchange,   the rate   constants and  bound   fraction is nonetheless   determined from an analysis of the spectra. The   analysis relies  on the expression   of 1D NMR  signal intensity   by a set of Bloch equations with exchange terms.  The time   span of the  binding and   dissociation of hydrophobic   FBPAto  large unilamellar   vesicles of egg   phosphatidylcholine (EPC) is  10-3  to 10-2 s. The rates of FBPA binding and dissociation   are kept constant per EPC molecule even at different   concentrations of the vesicle. The free energy of FBPA transfer   is -20±2  kJ/mol at 303 K.   The process is entropy-driven. The efficiency of FBPA transfer is   enhanced by a factor of 7×104, as   compared to the hydrophilic 5-fluorouracil.

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