Cy5 Azide

The NIR-fluorescent Cy5 azide can be reacted with terminal alkynes via a copper-catalyzed click reaction (CuAAC). It also reacts with strained cyclooctyne via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures. Cy5 is a water-soluble, bright fluorescent label that can be used in place of Alexa Fluor 647®, DyLight 649® and other dyes excitable at a wavelength of 633 or 647 nm.