[Formation of alpha-tocopherol complexes with fatty acids. Possible mechanism of biomembrane stabilization by vitamin...

It was demonstrated that saturated and unsaturated fatty acids form complexes with alpha-tocopherol in solution. The equilibrium constants for fatty acid interaction with alpha-tocopherol were determined. The values of these constants were practically independent of the number of carbon atoms in the saturated fatty acid molecule (from C7 to C24) and were of the order of 40-50 M-1. For unsaturated fatty acids this constant was exponentially increased with a rise in the number of double bonds in the fatty acid molecule (1,25 X 10(4) M-1 for arachidonic acid). It was shown that alpha-tocopherol can form complexes with free fatty acids incorporated into phosphatidyl choline liposomes or into skeletal muscle sarcoplasmic reticulum membranes. The complex formation between alpha-tocopherol and free fatty acids probably underlies the mechanism of biomembrane stabilization by vitamin E against the damaging action of free fatty acids.