Streptavidin is a non-glycosylated protein that is prepared chromatographically from the bacterium Streptomyces avidinii. Streptavidin homotetramers have a particularly high, non-covalent binding affinity for biotin. When conjugated with fluorochromes, streptavidin has been widely used with biotin-conjugated antibodies and other biotinylated specific-binding molecules (eg, recombinant proteins and lectins) to stain cells and tissues for subsequent multiparameter analysis by flow cytometry, fluorescence microscopy and imaging. Likewise, when conjugated with an enzyme (eg, Horseradish Peroxidase or Alkaline Phosphatase) and coupled with a colorimetric or luminescent substrate development system, streptavidin has found widespread use along with biotinylated antibodies in a number of applications including Western blot, ELISA, ELISPOT, immunocytochemistry and immunohistochemistry.
Streptavidin was conjugated to BD Horizon BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
