mFluor™ UV420 streptavidin conjugate comprises streptavidin (as the biotin-binding protein) with mFluor™ UV420 covalently attached. mFluor™ UV420 provides a unique color for fluorescence imaging and flow cytometric applications. It is used as a second step reagent for indirect immunofluorescent staining, when used in conjunction with biotinylated primary antibodies. AAT Bioquest offers the largest collection of streptavidin conjugates. They are widely used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids and other molecules since streptavidin has a very high binding affinity for biotin. The affinity between streptavidin and biotin might be the strongest non-covalent interactions known in biological interactions. Streptavidin, a homotetrameric protein, exhibits an extraordinarily high affinity for biotin. Each streptavidin monomer can bind one biotin molecule, allowing a streptavidin protein to maximally bind four biotins. The streptavidin-biotin interaction is highly specific and remains robust under a wide range of conditions.