AFDye™ 568 Maleimide (Alexa Fluor® 568 C5 Maleimide equivalent) is a bright, and highly photostable, orange-fluorescent probe optimally excited by the 568 nm laser line on the Ar-Kr mixed-gas laser. AFDye™ 568 Maleimide is water-soluble and its fluorescence is pH independent over a wide pH range. The brightness and photostability of this dye are best suited to direct imaging of low-abundance targets.
Maleimide is the most popular sulfhydryl-reactive reactive group for conjugating the dye to 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 bond. The resulting conjugates exhibit brighter fluorescence and greater photostability than the conjugates of many other spectrally similar fluorophores.
AFDye™ 568 Maleimide is structurally identical to Invitrogen’s Alexa Fluor® 568 C5 Maleimide