The DyLight™ Long Stokes Shift Dyes are amine-reactive fluorescent dyes that produce long Stokes (LS) shifts of 80 to 145 nm in excitation/emission wavelengths. The DyLight™ LS dyes provide multicolour detection using a single excitation source in applications including flow cytometry, conjugation, DNA-sequencing, microscopy and fluorescence in situ hybridization (FISH). These dyes contain N-hydroxysuccinimide (NHS) esters, the most commonly used reactive group for labeling proteins. NHS esters react with primary amines on proteins and other molecules, forming a stable, covalent amide bond and releasing the NHS group.