Use of electron paramagnetic resonance spectroscopy spin labels in studying the properties of biological membranes

: Electron paramagnetic resonance (EPR) spectroscopy of spin labels has become a widely spread method in biochemistry, molecular biology, and medicine. After a brief view on the structure and functions of biological membranes, basic principles of EPR and particularly of the spin labeling technique are presented. Applications of this technique are demonstrated on the study of various properties of biological membranes, such as phase transition of lipids, properties of different membrane parts, permeability of membranes, inner volumes of liposomes and cells, membrane potentials, lateral diffusion, lipid-protein interaction, and determination of oxygen concentration. As an example the results of a study concerning the effect of chlorpromazine and its derivatives on the dynamics and lipid-protein interaction in synaptosomes are presented.