Biochemical and Biophysical Research Communications
Glutathione peroxidase activity in selenium-deficient rat liver☆
Abstract
Glutathione peroxidase activity in the liver supernatant from rats fed a Se-deficient diet for 2 weeks was 8% of control when measured with H2O2 but 42% of control when assayed with cumene hydroperoxide. Two peaks of glutathione peroxidase activity were present in the Sephadex G-150 gel filtration chromatogram of rat liver supernatant when 1.5 mM cumene hydroperoxide was used as substrate. Only the first peak was detected when 0.25 mM H2O2 was used as substrate. The first peak was absent from chromatograms of Se-deficient rat liver supernatants; but the second peak, which eluted at a position corresponding to M.W. = 39,000, appeared unchanged. The second peak thus represents a second glutathione peroxidase activity which catalyzes the destruction of organic hydroperoxides but has little activity toward H2O2 and which persists in severe selenium deficiency.
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Supported by U.S.P.H.S. grants R01 ES-01017 (R.F.B.) and T32 AM-07100 (R.A.L.)