Vari Fluor 555-Streptavidin is a dye from the Vari Fluor series, designed by labeling streptavidin with fluorescent probes. Streptavidin is a tetrameric protein with high affinity, comprised of four identical subunits, and it can specifically bind to biotin through reversible non-covalent interactions. This property allows streptavidin to enable the rapid and efficient detection of biotin-labeled molecules, making it a valuable tool in experiments such as immunofluorescence (IF), enzyme-linked immunosorbent assays (ELISA), immunohistochemical staining (IFH), and in situ hybridization. The excitation/emission wavelengths are 555 nm/565 nm.