Tocopherol activity correlates with its location in a membrane: A new perspective on the antioxidant vitamin e

Document Type

Article

Publication Date

5-22-2013

Publication Title

Journal of the American Chemical Society

Volume

135

Issue

20

First Page

7523

Last Page

7533

Abstract

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. © 2013 American Chemical Society.

DOI

10.1021/ja312665r

ISSN

00027863

E-ISSN

15205126

PubMed ID

23581571

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