Electrooptical and biophysical measurements on membrane fragments

Membranes of biological origin have an inherent electric asymmetry. In such cases, when not closing fragments are separated by fractionation from organisms, membranes with permanent electric dipole moment in addition to induced dipole moment (polarizability) originate. In this paper, electrooptical studies on purple membrane (pm) containing the protein bacteriorhodopsin (bR) from Halobacterium salinarum and membrane fragments from pig kidney containing Na+K+ATP-ase are surveyed. It is also pointed out that vectorial biological processes, such as charge translocations by proteins in membranes, may be applied to determine whether the membranes have permanent dipole moment. Examples of this type of studies are the halorhodopsin (hR) containing membrane from H. salinarum and the photosynthetic membrane from alga Chlamidomonas reinhardtii.