NADP+/NADPH Colorimetric Assay Kit

NADP⁺/NADPH is a core cellular redox couple essential for biosynthesis, redox defense, and metabolism. Quantifying their levels and ratio is critical for evaluating redox status and metabolic function. Conventional ultraviolet absorption assays at 340 nm suffer from limited sensitivity, interference, and high sample consumption. Therefore, developing more robust and sensitive detection methods is of great importance.

This kit is designed to measure NADP⁺ concentration, NADPH concentration and NADP⁺/NADPH ratio. In this assay, glucose-6-phosphate dehydrogenase (G6PDH) can catalyze the reaction of G6P to generate 6-PG, during the reduction of NADP⁺ to NADPH. Subsequently, NADPH reduces WST-8 to an orange formazan with a maximum absorbance at 450 nm. The absorbance is directly proportional to the amount of NADP⁺ and NADPH in the sample. For the specific determination of NADPH, heat samples at 60°C for 30 min to completely degrade NADP⁺, and perform the same reaction system to quantify the NADPH concentration only. Finally, calculate the NADP⁺/NADPH ratio based on the NADP⁺ and NADPH concentrations.

Figure 1. Typical standard curve and assay data. (A) Measure the NADP+/NADPH ratio, (B) NADP+ and NADPH concentration in Hela, 293T and Jurkat cells, (C) NADPH calibration standard curves, which are not interfered with by NADH.