HiLyte Fluor™ TR -streptavidin conjugate has been optimized in fluorophore/protein labeling ratio to ensure high fluorescent signal and uncompromised streptavidin function. HiLyte Fluor™ TR has comparable spectral properties to those of sulforhodamine 101 sulfonyl chloride (also called Texas Red®) with stronger fluorescence intensity. The fluorescence of HiLyte Fluor™ TR can be observed at excitation/emission wavelength of 591 nm / 622 nm. The HiLyte Fluor™ TR-protein conjugates are very stable and are suitable for immunofluorescent staining, fluorescence in situ hybridization, flow cytometry and other biological applications.