(H-Asp-Glu-Val-Asp)₂-Rhodamine 110

(DEVD)?-R110, non-fluorescent peptidyl (DEVD)-Rhodamine 110-bisamide, is a highly sensitive, photostable fluorogenic substrate for the determination of caspase-3 activity. Characteristic for substrates based on Rhodamine 110 (R110) is that they contain two identical amino acids or peptides attached to a single fluorophor thereby suppressing its visible absorption and its fluorescence. Upon enzymatic cleavage, this substrate is converted first to the fluorescent monoamide and then to the even more fluorescent R110. The spectral properties of these hydrolysis products are similar to those of fluorescein, with peak excitation and emission wavelengths of 496 and 520 nm, respectively. The fluorescence intensity can be measured by flow cytometry, microwell plate reader, or fluorescence microscopy. Useful for high throughput screening applications.