Assays of nicotinamide nucleotides are of continual interest in the studies of energy transforming and redox state of cells or tissue. The NADP/NADPH Quantification Kit provides a convenient tool for sensitive detection of the intracellular nucleotides: NADP, NADPH and their ratio. The enzymes in the system specifically recognize NADP/NADPH in an enzyme cycling reaction (It does not recognize NADᶧ/NADH). There is no need to purify NADP/NADPH from sample mix. The enzyme cycling reaction significantly increases detection sensitivity. Results can be quantified using plate reader at OD450 nm.