The OxiSelect™ Total Glutathione Assay Kit is a quantitative assay for measuring the total glutathione content within a sample (GSH/GSSG). Glutathione Reductase reduces oxidized glutathione (GSSG) to reduced glutathione (GSH) in the presence of NADPH. Subsequently, the chromogen reacts with the thiol group of GSH to produce a colored compound that absorbs at 405 nm. The total glutathione content in unknown samples is determined by comparison with the predetermined glutathione standard curve. The rate of chromophore production is proportional to the concentration of glutathione within the sample. The rate can be determined from the absorbance change over time. Metaphosphoric acid is provided to remove interfering proteins or enzymes from samples.
Figure 1: GSSG Standard Curve. OD 405nm versus incubation time as a function of GSSG concentration.