AAT Bioquest's iFluor(TM) 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(TM) 350 dyes have fluorescence excitation and emission maxima of ~350 nm and ~440 nm respectively. These spectral characteristics make them an excellent alternative to AMCA and Alexa Fluor(R) 350 labeling dye (Alexa Fluor(R) is the trademark of Invitrogen). iFluor(TM) 350 amine is stable and used for modifying carbonyl groups (e.g., aldehyde and carboxy groups).