AFDye™ 488 (Alexa Fluor® 488 equivalent) is a water-soluble, highly photostable dye with a very high fluorescence quantum yield. AFDye™ 488 has green fluorescence that is pH independent from pH 4 to pH 10 with excitation ideally suited for the 488 nm laser line. Its green fluorescence is pH independent from pH 4 to pH 10. AFDye™ 488 dye can be conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates which are often used for generation of stable signals in imaging and flow cytometry.
Maleimide is the most popular sulfhydryl-reactive reactive group for conjugating the dye to either a thiol group on a protein, oligonucleotide thiophosphate, or low molecular weight ligand. The maleimide group specifically and efficiently reacts with reduced thiols (sulfhydryl groups, –SH) at pH 6.5 to 7.5 to form stable thioether bonds. The resulting conjugates exhibit brighter fluorescence and greater photostability than the conjugates of many other spectrally similar fluorophores.
AFDye™ 488 Maleimide dye is structurally identical to Invitrogen’s Alexa Fluor® 488 C5 Maleimide dye.