Inhibition of 5-lipoxygenase by vitamin E

Abstract

Purified 5-lipoxygenase from potato tubers was inhibited strongly by vitamin E and its analogs. The inhibition by d-α-tocopherol was found to be irreversible and non-competitive with respect to arachidonic acid. An IC50 of 5μM was calculated for d-α-tocopherol. The inhibition appears to be unrelated to its antioxidant function. Binding studies with 14C-labelled d-α-tocopherol revealed that there is a strong interaction between vitamin E and 5-lipoxygenase. Tryptic digestion and peptide mapping of 5-lipoxygenase-vitamin E complex indicate that vitamin E binds strongly to a single peptide. These studies suggest that cellular vitamin E levels may have profound influence on the formation of leukotrienes. © 1985.