The Alexa Fluor 647 goat anti—human IgG is labeled with our exceptionally bright far-red—fluorescent Alexa Fluor 647 dye (which is spectrally similar to Cy5 dye) and is prepared from affinity-purified antibodies that react with IgG heavy chains and all classes of immunoglobulin light chains from human. To minimize crossreactivity, it has been adsorbed against mouse, rabbit and bovine serum prior to conjugation.