Cy5.5 Amine (also sold as sulfo-Cyanine5.5 Amine) is a bright and photostable near-IR dye that spectrally similar to Alexa Fluor® 680, DyLight® 680, and IRDye® 680 dye. Cy5.5 Amine is a very hydrophilic, water-soluble and pH insensitive from pH 4 to pH 10. A significant advantage to using long wavelength dyes such as Cy5.5 or Alexa Fluor® 680 dye over other fluorophores is the low autofluorescence of biological specimens in this region of the spectrum. Fluorescence of this long-wavelength Cyanine dye is not visible to the human eye but is readily detected by most imaging systems.
Cy5.5 Amine is a carbonyl reactive building block used to modify carboxylic groups in the presence of activators (e.g. EDC, or DCC) or activated esters (e.g. NHS esters) through a stable amide bond. It also can be employed as a polar tracer, a reactive dye for labeling proteins via a carboxylic acid moiety, and amine donor for enzymatic transamination labeling.