Formation of alpha-tocopherol complexes with fatty acids. A hypothetical mechanism of stabilization of biomembranes by vitamin E.
The formation of alpha-tocopherol complexes with saturated and unsaturated fatty acids in ethanol has been demonstrated. The values of equilibrium constants for alpha-tocopherol interactions with fatty acids have been determined. These values do not depend in practice on the number of carbon atoms in saturated fatty acid molecules (from 7:0 to 24:0) and are equal to about 40-50 M-1. For unsaturated fatty acids the values of equilibrium constants are increased exponentially with an increase in the number of double bonds in the fatty acid molecule (1.25 X 10(4) M-1 for arachidonic acid). alpha-Tocopherol can form complexes with free fatty acids incorporated into phosphatidylcholine liposomes or into skeletal muscle sarcoplasmic reticulum membranes. The formation of alpha-tocopherol complexes with free fatty acids is regarded as a molecular mechanism of membrane stabilization by vitamin E against the damaging action of free fatty acids.
D000818:Animals; D005227:Fatty Acids; D007700:Kinetics; D008081:Liposomes; D008563:Membrane Lipids; D008954:Models, Biological; D011817:Rabbits; D012519:Sarcoplasmic Reticulum; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014810:Vitamin E
D005227:Fatty Acids; D008081:Liposomes; D008563:Membrane Lipids; D014810:Vitamin E