2.9. Thioredoxin Reductase (TrxR) Activity Assay

One millilitre assays contained 50 mM K₂HPO₄ buffer, pH 8.0 with 1% ethanol, 1 mM EDTA, 3 mM 5,5′-dithiobis (2-nitrobenzoate) (DTNB), 0.2 mM of either NADPH or NADH and 2 μM TrxR. DTNB-related absorbance changes were monitored at 412 nm [29], and activity was calculated using an extinction coefficient of 13.6 mM⁻¹ cm⁻¹.