Tetrazolium salt, abbreviated to MTT, is used for detection of dehydrogenases in combination with phenazine methosulfate (cat. no. 32030) (1). MTT is utilized as a colorimetric metabolic activity indicator in cell viability assays and to determine cell proliferation (3, 4). It works as a terminal electron acceptor in the cycling assay for pyridine nucleotides (2). MTT produces a yellowish solution that is converted to dark blue, water-insoluble MTT formazan by mitochondrial dehydrogenases of living cells. The blue crystals are solubilized with acidified isopropanol and the intensity is measured colorimetrically at 570 nm. Tetrazolium salt, abbreviated to MTT, is used for detection of dehydrogenases in combination with phenazine methosulfate (cat. no. 32030) (1). MTT is utilized as a colorimetric metabolic activity indicator in cell viability assays and to determine cell proliferation (3, 4). It works as a terminal electron acceptor in the cycling assay for pyridine nucleotides (2). MTT produces a yellowish solution that is converted to dark blue, water-insoluble MTT formazan by mitochondrial dehydrogenases of living cells. The blue crystals are solubilized with acidified isopropanol and the intensity is measured colorimetrically at 570 nm.