Dielectric dispersions in bacteriorhodopsin

Dispersion effects in bacteriorhodopsin both in suspension and incorporated into liposomes have been studied by measuring the changes in the dielectric properties induced by electric and magnetic fields at low and medium frequencies. The samples exhibit very high values of relative permittivity and dielectric loss. Dispersions have been measured up to 200 kHz and are believed to be due to the reorientation of the bacteriorhodopsin chromophore within the membrane fragments. A study of relaxation times vs temperature shows a transition at 28°C, the same temperature as found using other techniques.