This is a a sensitive fluorogenic substrate for elastase and trypsin, Abs/Em=501/527 nm. The colorless and nonfluorescent (Z-Ala-Arg)2Rh110 is hydrolyzed to the highly fluorescent Rhodamine 110, which exhibits excellent spectral properties that match the optimal detection window of most fluorescence instruments. After cleavage, the Abs(max) is at 497 nm and Em(max): is at 527 nm.