Resazurin is effectively reduced in mitochondria, making it useful also to assess mitochondrial metabolic activity.
Usually, in the presence of NADPH dehydrogenase or NADH dehydrogenase as the enzyme, NADPH or NADH is the reductant that converts resazurin to resorufin. Hence the resazurin/diaphorase/NADPH system can be used to detect NADH, NADPH, or diaphorase level, and any biochemical or enzyme activity that is involved in a biochemical reaction generating NADH or NADPH.
Resazurin can be used to assay L-Glutamate, achieving a sensitivity of 2.0 pmol per well in a 96 well plate.
Resazurin can also be used to measure the aerobic biodegradation of organic matter found in effluents.
Resazurin is used to measure the amount of aerobic respiration in streams. Since most aerobic respiration occurs in the stream bed, the conversion of resazurin to resorufin is also a measure of the amount of exchange between the water column and the stream bed.