34994-50-8

Dark Purple Solid

Resorufin is a pink fluorescent dye that is not fluorescent until activated by UV light. Resorufin is an anionic tricyclic dye.

The free acid is purified by dissolving it in conc H2SO4 which on dilution precipitates resorufin and is filtered off, washed well with hot H2O and dried. [Eichler J Prakt Chem 139 113 1934.] Detailed UV and IR studies were reported by Musso & Mattheis Chem Ber 90 1814 1957]. [pKa: Musso & Rathjen Chem Ber 92 751 1959, Beilstein 27 1V 2263.] The monoacetate [1152-14-3] M 252.2, m 2 2 3o is a fluorogenic substrate used for hydrolytic enzymes, and its fluorescence has Emax 593nm (Eex 500nm, in 0.1M phosphate pH 8.0 with lipase) [Kitson & Kitson Biochem J 322 701 1997]. [Beilstein 27 IV 2263.] The O7-methylresorufin (7-methoxy-3H-phenoxazin-3-one) [5735-89-3] M 227.2, m > 2 2 0o has fluorescence at Emax 585nm (Eexcit 571 nm in deacylase solution) and is used to differentiate isoenzymes of cytochrome P-450. It is insoluble in H2O and dilute alkali but is soluble in EtOH and CHCl3 to give an orange yellow colour. [Kehrmann Justus Liebigs Ann Chem 372 352 1910, Beilstein 27 II 108.]