iFluor® 500 dyes have fluorescence excitation and emission maxima of ~500 nm and ~520 nm respectively. The spectra fill the spectral gap between Alexa Fluor® 488 and Alexa Fluor 514 labeling dyes (Alexa Fluor® is the trademark of ThermoFisher). iFluor® 500 SE is reasonably stable and shows good reactivity and selectivity with protein amino groups. AAT Bioquest's iFluor® dyes are optimized for labeling proteins, in particular, antibodies. These dyes are bright, photostable and have minimal quenching on proteins. They can be well excited by the major laser lines of fluorescence instruments (e.g., 350, 405, 488, 555 and 633 nm). iFluor dyes span the broadest spectra from UV (320 nm) to IR (900 nm).