IR 750 Maleimide (IRDye® 750 Maleimide analog) is a water-soluble, bright, near-IR fluorescent dye that is spectrally similar to other 750 dyes used for flow cytometry, microscopy and other applications. IR 750 conjugates ideally suited for the 633 nm laser lines or dye-pumped laser. A significant advantage to using long wavelength dyes such as Cy7® Dye or Alexa Fluor® 750 dye over other fluorophores is the low autofluorescence of biological specimens in this region of the spectrum. IR 750 conjugates are is pH-insensitive over a wide molar range, helping ensure that you get stable signals in imaging and flow cytometry applications.
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.