1 research outputs found
Tocopherol Activity Correlates with Its Location in a Membrane: A New Perspective on the Antioxidant Vitamin E
We show evidence of an antioxidant
mechanism for vitamin E which
correlates strongly with its physical location in a model lipid bilayer.
These data address the overlooked problem of the physical distance
between the vitamin’s reducing hydrogen and lipid acyl chain
radicals. Our combined data from neutron diffraction, NMR, and UV
spectroscopy experiments all suggest that reduction of reactive oxygen
species and lipid radicals occurs specifically at the membrane’s
hydrophobic–hydrophilic interface. The latter is possible when
the acyl chain “snorkels” to the interface from the
hydrocarbon matrix. Moreover, not all model lipids are equal in this
regard, as indicated by the small differences in vitamin’s
location. The present result is a clear example of the importance
of lipid diversity in controlling the dynamic structural properties
of biological membranes. Importantly, our results suggest that measurements
of aToc oxidation kinetics, and its products, should be revisited
by taking into consideration the physical properties of the membrane
in which the vitamin resides