AZDye 660 Maleimide

AZDye 660 is a bright and photostable near-IR dye that is spectrally almost identical to Alexa Fluor® 660 and CF660® 680RD. AZDye 680 is often used for a bright and photostable far-red dye with excitation ideally suited to the 633 or 647 nm laser line. AZDye 660 ideally suited for the 633 nm laser line. This near-IR fluorescent dye is water soluble and pH-insensitive from pH 4 to pH 10. AZDye 660 molecules can be attached to proteins at high molar ratios without significant self-quenching, leading to brighter conjugates and more sensitive detection. The long wavelength emission allows for detection in complex samples with auto-fluorescent background signals.

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 bonds.