The fluorecent protein is often used to study protein localization, reporter gene expression and protein-protein interaction. YFP (yellow fluorescent protein), a genetic mutant of green Fluorescent Protein (GFP), migrates its fluorescence to the red spectrum mainly because the threonine at position 203 of GFP is replaced by tyrosine. The yellow fluorescent protein fusion protein can spontaneously fluoresce. The localization of the target gene in the cell can be detected without antibody hybridization of the target protein, with little interference from other substances. The agarose can be used for immunoprecipitation, co-immunoprecipitation, affinity chromatography of natural YFP and their fusion proteins. Anti-YFP Affinity Beads 4FF can also detect and purify GFP, EGFP and their fusion proteins . It cannot bind BFP fusion protein.