Nicotinamide adenine dinucleotide-tetrazolium

Nicotinamide adenine dinucleotide Tetrazolium violet Diaphorase... 

The biological applications of tetrazolium salts are the subject of a textbook.96 Kuhn and Jerchel74 were the first to recognize the utility of tetrazolium salts as indicators in redox enzyme activity, particularly those of the various dehydrogenases. It has been recognized449 that this particular utility of tetrazolium salts is related to the proximity of their redox potentials to those of the hydride transfer systems in biology450 such as nicotinamide adenine dinucleotide, NAD, and its phosphate analogue, NADP. 

The MT T assay is another colorimetric method to assess cell viability. NAD(P)H (nicotinamide adenine dinucleotide(P)H)-dependent cellular oxidoreductase enzymes may, under defined conditions, reflect the number of viable cells present. These enzymes are capable of reducing the tetrazolium dye MTT 3-(4,5-diwiethylfhiazol-2-yl)-2,5-diphenylletrazolium bromide to its insoluble purple-coloured formazan (Figure 7.71). In living cells, the originally yellow MTT is converted by cellular reductase to purple formazan (Mosmann, 1983). A solubilisation solution (usually either dimethyl sulfoxide or sodium dodecyl sulfate dissolved in diluted hydrochloric acid) is added to dissolve the insoluble... 

NADH/NAD = nicotinamide adenine dinucleotide, pyruvate = pyruvic acid, formazan = tetrazolium dye, LDH = lactate dehydrogenase. 

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