Resorufin

Resorufin is a stable red fluorophore standard widely used in biochemical and molecular biology research. It is used in enzyme assay systems (e.g. Amplex Red) and as an indicator of cell viability in assays. Resorufin represents the reduced dye formed from Amplex Red reaction or resazurin reductions. One common application of resorufin is in the measurement of mitochondrial activity. When cells are metabolically active, they can reduce resazurin to resorufin, producing a measurable fluorescent signal. This property makes resorufin a valuable tool in various research applications, such as assessing cell health, drug screening, and enzyme activity studies. It is unstable in the presence of thiols such as dithiothreitol (DTT) and 2-mercaptoethanol. This compound can be used as a standard for enzyme substrates whose end product is resorufin. Resorufin is also a highly selective and potent inhibitor of protein kinase CK2 useful as a lead compound. Resorufin is an important organic fluorophore/chromophore and building block, frequently utilized in the development and synthesis of responsive probes for fluorescence and colorimetric analysis. To date, more than 100 probes have been developed based on the resorufin scaffold. This is mainly because resorufin exhibits unique photophysical properties, such as long excitation and emission wavelength (572/585 nm), high fluorescence quantum yield (φ = 0.74 in water), and large molar absorptivity (56000 M-1 cm-1), and favorable stability to light irradiation and pH changes (pH 6.0-10.0). The fluorescence intensity of the resorufin dye could be easily regulated by modification of its chemical structure, which facilitates the application of this fluorophore to the development of responsive fluorescent probes for bioassay. Spectral Data. λEx/Em = 563/587nm (pH 9).