Abstract
A transmembrane proton gradient was created using a model liposome system. Internal ferricyanide served as an oxidant, phenazine methosulfate acted as an electron carrier, facilitating the transport of protons within the liposome membrane, and external ascorbate provided a source of electrons for exchange with electron carriers. Sodium thiosulfate was substituted for ascorbate to achieve a more feasible mechanism that coincided with the types of compounds that would have been found on prebiotic earth. 9-aminoacridine fluorescence was used to measure the internal pH of the liposome system to indicate the formation of a proton gradient. Triton X-100 was used to disrupt the lipid membrane and cause diffusion of protons to restore initial pH. The study found that the ascorbate liposome model induced a proton gradient which ensured that the mechanism worked. The thiosulfate system achieved formation of an internal proton gradient, as seen by a change in internal pH, however, reversal of the proton gradient was not fully obtained alluding to external factors also influencing results. Instead, confirmation of the thiosulfate system was done by examining the leaking of protons which was seen in the 9-aminoacridine fluorescence analysis.