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

To characterize the binding of tetraphenylborate (TPB) and tetraphenyl arsonium (TPAs) ions to bilayer liposomes the high resolution H-1 NMR was used to measure the chemical shifts and the relaxation times. In t he presence of small vesicles from egg PC or DOPC the NMR spectrum of TPB shows dramatic changes, in contrast to the small binding effect on TPAs. The analysis of the NMR signals of the membranes shows that the binding sites are located in the phospholipid headgroup and in the gl ycerol region. There is a strong evidence for the direct involvement o f the N+(CH3)(3) group into the binding process of TPB.