HiLyte Fluor™ 555-streptavidin conjugate has been optimized in fluorophore/protein labeling ratio to ensure high fluorescent signal and uncompromised streptavidin function. The spectrum of HiLyte Fluor™555 is only slightly red-shifted compared to those of Cy3™ dyes, resulting in an optimal match to filters designed for Cy3™ dyes. The fluorescence of HiLyte Fluor™ 555 can be observed at excitation/emission wavelength of 554 nm /570 nm. HiLyte Fluor™ 555 is more photostable than Cy3™, providing researchers with additional time for capturing image. HiLyte Fluor™555 - protein conjugates can sustain treatments during immunofluorescent staining, fluorescence in situ hybridization, flow cytometry and other biological applications without hydrolysis.