According to the localization of cell, Glutathione-S-transferase (GSH-ST) is divided into three subfamilies: cytoplasmic GSH-ST, microsomal GSH-ST and peroxisome/mitochondrial GSH-ST. GSH-ST is a kind of detoxifying enzyme. Maintain cell integrity by catalyzing the binding of reduced glutathione to electron-friendly substance. 

GST can catalyze the binding of reduced glutathione (GSH) to dinitrobenzene (CDNB) and the product have an absorption peak at 340 nm. The activity of GSH-ST can be calculated by measuring the increasing rate of absorbance at 340 nm.

    1.   The Reagent 3 application solution and cuvette should be preheat at 37℃ for 10 min

    2.   The reaction time must be accurate.

1.   Preheat the Reagent 3 application solution and cuvette at 37℃ for 10 min. Set the spectrophotometer to 340 nm and set the spectrophotometer to zero with double distilled water.

2.   Blank well: add 0.1 mL of Reagent 1 to a 2 mL EP tube.

Sample well: add 0.1 mL of sample to a 2 mL EP tube.  

3.    Add 0.9 mL of Reagent 2 and 0.1mL of Reagent 3 application solution to each tube, mix fully and record the time immediately. Measure the absorbance at 340 nm at 20 s (A1) and 320 s (A2), respectively. Calculate the △A=A2-A1.