Abstract: Provided is a real-time imaging method of NAPDH-dependent metabolic activity in a cell and a use thereof, and more particularly, an imaging method capable of measuring concentration gradient and change in an intracellular coenzyme using a mutant of metagenome-derived blue fluorescent protein (mBFP) in real-time and an application method thereof. In particular, the method of imaging and quantifying the coenzyme contained in various biological samples may be performed by improving fluorescence in a short time even under anaerobic conditions, without adding a substrate required for coenzyme measurement or conversion without destroying cells, and without consuming the time required for formation of a special structure (fluorophore) for generating fluorescence unlike the existing quantitative systems.