The Alexa Fluor 680 goat anti—mouse IgG is labeled with our bright, far-red—fluorescent Alexa Fluor 680 dye and is prepared from affinity-purified antibodies that react with IgG heavy chains and all classes of immunoglobulin light chains from mouse. To minimize crossreactivity, it has been adsorbed against human IgG and human serum prior to conjugation. We also provide a version of the same antibody that has been cross-adsorbed against additional species (Catalog number: A-21058). Fluorescence of this long-wavelength Alexa Fluor dye is not visible to the human eye but is readily detected by most imaging systems.