Notes: Resorufin β-D-galactopyranoside is a fluorogenic substrate for β-galactosidase.{50356} Upon enzymatic cleavage by β-galactosidase, the fluorescent moiety resorufin is released and its fluorescence can be used to quantify β-galactosidase activity. Resorufin displays excitation/emission maxima of 570/580 nm, respectively.