AFDye™ 488 (Alexa Fluor® 488 equivalent) is a green-fluorescent, water-soluble dye with pH insensitive emission from pH 4 to pH 10. This dye is ideally suited to the 488 nm laser line. AFDye 488 is one of the brightest dyes commercially available with fluorescence quantum yield close to 100%.
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 Alexa Fluor® 488 C5 Maleimide dye.