Amplite® Fluorimetric NADPH Assay Kit *Red Fluorescence*

Protocol summary

1. Prepare NADPH working solution (50 µL)
2. Add NADPH standards or test samples (50 µL)
3. Incubate at room temperature for 15 minutes - 2 hours
4. Monitor fluorescence increase at Ex/Em = 540/590 nm

Important notes
Thaw one of each kit component at room temperature before starting the experiment.

1. NADPH standard solution (1 mM):
Add 200 µL of PBS buffer into the vial of NADPH standard (Component C) to make 1 mM (1 nmol/µL) NADPH stock solution.

Add 10 mL of Amplite™ NADPH Assay Buffer (Component B) into the bottle of NADPH Recycling Enzyme Mixture (Component A); mix well. Note: This NADPH working solution is enough for two 96-well plates. The working solution is not stable, use it promptly and avoid direct exposure to light.

Table 1. Layout of NADPH standards and test samples in a solid black 96-well microplate. NS = NADPH standard (NS1 - NS7, 0.1 to 100 µM); BL = blank control; TS = test sample.

Table 2. Reagent composition for each well

1. Prepare NADPH standards (NS), blank controls (BL), and test samples (TS) into a solid black 96-well microplate according to the layout provided in Table 1 and Table 2. For a 384-well plate, use 25 µL of reagent per well instead of 50 µL. Prepare cells or tissue samples as desired.
   
   
2. Add 50 µL of NADPH working solution to each well of NADPH standard, blank control, and test samples to make the total NADPH assay volume of 100 µL/well. For a 384-well plate, use 25 µL of working solution into each well instead, for a total volume of 50 µL/well.
   
   
3. Incubate the reaction at room temperature for 15 minutes to 2 hours, protected from light.
   
   
4. Monitor the fluorescence increase with a fluorescence plate reader at Excitation = 530 - 570 nm, Emission = 590 - 600 nm (optimal Ex/Em = 540/590 nm). Note: The contents of the plate can also be transferred to a white clear bottom plate and read by absorbance microplate reader at the wavelength of 576 ± 5 nm. However, the absorption detection will have a lower sensitivity compared to fluorescence reading. For cell based NADPH measurements, ReadiUse™ mammalian cell lysis buffer *5X* (Cat No. 20012) is recommended to use for lysing the cells.