NOTE 1 H NMR Study of the Interaction of Aluminum(III) with Phosphatidylcholine Vesicles chromatography until it gave a single spot. The purified PC was stored as a 5% (w/v) chloroform stock solution. AlCl 3 r6H 2 O, EuCl 3 r6H 2 O, In-The interaction of aluminum(III) with phosphatidylcholine Cl 3 r4H 2 O, and all the other metal chlorides are reagent grade and dried (PC) small unilamellar vesicles (SUV) was investigated by 1 H under vacuum for 4 h at ambient temperature before use. NMR utilizing EuCl 3 as a shift reagent. An upfield shift of outward facing choline methyl signal of PC SUV was induced by addition PC SUV Preparation of Eu 3/ to a PC SUV suspension. This was markedly reduced by subsequent addition of AlCl 3 and InCl 3 to the suspension. Addition Five milliliters of the PC stock solution was evaporated and the residue of several other divalent metal chlorides (MgCl 2 , CaCl 2 , NiCl 2 , was dried under vacuum for 4 h. The dried residue was suspended in 5.0 and ZnCl 2 ) did not reduce the Eu 3/ -induced shift. The line broad-mL of 100 mM NaCl-D 2 O using a vortex mixer. Then the suspension was sonicated to produce SUV's. Three minutes of sonication with 3 min inter-ening of choline methyl signal brought about by addition of Fe 2/ or vals was repeated 15 times under a nitrogen stream in an ice-water bath. Fe 3/ to PC SUV suspensions was further enhanced by subsequent The sonicated suspension was centrifuged for 20 min at 2000g (3500 rpm) addition of AlCl 3 . From these results, we conclude that Al 3/ and to eliminate sediment from the sonication tip. The concentration of PC in In 3/ interact with the phosphate group of PC molecules on the the stock solution and the PC SUV suspension was confirmed by phosphorus outer surface of SUV and displaces the bound Eu 3/ . The interacdetermination (12). The pH value of PC SUV samples containing metal tion of Fe 2/ and Fe 3/ with PC SUV appears to be enhanced by chlorides was 3.5 { 1 pH unit. Al 3/ . Our results also indicate that In 3/ binds stronger to PC SUV than Al 3/ .