The Alexa Fluor 488 donkey anti—rat IgG is labeled with our bright, photostable, green-fluorescent Alexa Fluor 488 dye and is prepared from affinity-purified antibodies that react with IgG heavy chains and all classes of immunoglobulin light chains from rat. The donkey anti—rat IgG antibodies show minimum crossreactivity to bovine, chicken, goat, guinea pig, hamster, horse, human, mouse, rabbit and sheep serum proteins.