Figure 3.

GPx-like activity assay in buffer solution and in methanol. (A) Nicotinamide adenine dinucleotide phosphate (NADPH)-coupled GPx assay for selenides 5–9. Reaction conditions were [GSH]₀ = 1.0 mM, [H₂O₂]₀ = 2.5 mM, [NADPH]₀ = 0.3 mM, [glutathione reductase] = 4 units/mL, and [selenide] = 0.2 mM in pH 7.4 phosphate buffer at 25 °C. (B) Percentages of residual dithiothreitol (DTT^red) as a function of reaction time in the oxidation of DTT^red with H₂O₂ in the presence of a selenide catalyst (5–9) in CD₃OD. Reaction conditions were [DTT^red]₀ = [H₂O₂]₀ = 0.14 M and [selenide] = 0.014 M at 25 °C. Data for 7‒9 were quoted from Reference [29].