Nicotinamide nucleotides are key players in the energy transforming and oxidation-reduction reactions of a cell. NADP and NADPH act as allosteric effectors in modulating enzyme activities. The reducing power of NADPH is a required cofactor for enzymes that are pro-oxidants, such as nitric oxide synthase and NADPH oxidase. NADP/NADPH ratio is involved in the control of the oxidative shunt. Each of these forms has a particular role during differentiation and similarity processes as well as being target functions in the cytotoxic action of ionizing radiations and alkylating agents. The SensoLyte® NADP/NADPH Assay Kit utilizes an optimized enzymatic recycling method for the quantification of NADP/NADPH without interfering with NAD/NADH. NADP is converted to NADPH in this enzyme-cycling reaction. The kit contains a fluorogenic reagent, producing fluorescence when reacted with NADPH. The resulting red fluorescence can be monitored at excitation /emission= 560/590 nm. The intensity of the fluorescence produced is proportional to NADP/NADPH concentration.