AUTOPOIETIC SELF-REPRODUCTION OF CHIRAL FATTY-ACID VESICLES

The self-reproduction of vesicles formed by (S)- and (R)-2-methyldodec anoic acid (4) was investigated in order to relate the autocatalytic i ncrease of the vesicle concentration with enantioselectivity. 4(R) and 4(S) were synthesized with an enantiomeric excess greater than 98%. 4 forms vesicles in aqueous solution in the pH region between 8.8 and 7 .5. Chiral properties of the vesicles were studied by differential sca nning calorimetry (DSC) and circular dichroism (CD). For self-reproduc tion studies, the hydrolysis of the water-insoluble 2-methyldodecanoic anhydride (8) was investigated in a biphasic system consisting of an aqueous solution and 8. The reaction rates of 8(RR) and 8(SS) catalyze d by 4(R) or 4(S) vesicles were the same within experimental errors, i ndicating that the chiral vesicles cannot induce significant enantiose lectivity. However, a clear effect was observed at 10 degrees C: racem ic vesicles destabilized during hydrolysis; causing phase separation, whereas homochiral vesicles remained stable and continued to self-repr oduce.