RESUMO
The incorporation of pyrene within the membrane interior of goat erythrocyte ghost has been estimated from its fluorescence spectrum. The excimer to monomer fluorescence intensity ratio of embedded pyrene is a function of the fluidity of its environment and the magnitude of its incorporation. Our study shows that this ratio is considerably less (30%) in a pre-sealed ghost than in the non-sealed ghost revealing that the site of incorporation of the probe is indeed the hydrophobic interior of the membrane; as in the later case, the probe has access to the membrane interior from both sides of the membrane. Our study on kinetics of molecular exchange indicates a very fast (of the order of seconds) transfer rate of pyrene from probed to unprobed erythrocyte ghosts through the aqueous phase rather than actual fusion of the membranes.