Sulfo-Cyanine3 NHS Ester is a derivative compound of Cy3 NHS Ester (C951305). Cy3 NHS Ester is a fluorescent dyes typically used for imaging applications. Cy3 NHS Ester is a fluorescent dye suitable for labeling proteins and nucleic acids. It exhibits excitation and emission at 555 nm and 570 nm, respectively. Cy3 NHS Ester can be used to label functional nucleic acids to detect tertiary structure folding such as guanine quadruplex.