Water-soluble Cy®5 dyes are the most commonly used fluorescent labeling reagents for preparing far-red fluorescent bioconjugates. Cy5® conjugates are very bright, photostable, pH insensitive and produce minimal autofluorescence of biological specimens in this region of the spectrum. Water-soluble Cy5® dye can be used in place of Alexa Fluor 647®, DyLight 649® and other dyes excitable at a wavelength of 633 or 647 nm.
This sulfonated dye is also known as sulfo-Cyanine5 Acid. Cy®Dye is a trademark of GE Healthcare.