THE TRANSFER OF HYDROPHOBIC TETRAPHENYLIONS ACROSS LIPID-MEMBRANES - KINETIC AND NMR INVESTIGATIONS - PART I - KINETIC INVESTIGATIONS

Impedance spectroscopic investigations of the transfer of tetraphenylb orate ions through lipid membranes show that the lipid headgroup consi derably influences the ion transfer. To characterize this influence ph ysicochemically, the rate constants of the ion transfer were elucidate d. The analysis reveals that the desorption of the ions from the membr ane surface into the electrolyte solution is the rate-determining step in the membrane ion transfer. This desorption is about one order of m agnitude slower than the ion translocation across the hydrophobic memb rane interior.