Streptavidin conjugates can be used to detect biotinylated molecules with extremely high sensitivity. They are commonly used as secondary reagents to detect biotinylated primary probes such as antibodies in flow cytometry, Western blotting, immunocytochemistry and other applications.

The red fluorescent protein R-phycoerythrin (R-PE) belongs to the family of phycobiliproteins, which are derived from cyanobacteria and eukaryotic algae. R-PE has absorption maxima at 496, 546, and 565 nm respectively and emission at 578 nm. Because of its high extinction coefficient (~1960000) and high fluorescence quantum yield (~0,82), R-PE is by far the brightest dye for the 565 nm wavelength region.

Concentration: 0,5 mg/ml in pH~7.4 PBS containing 2 mg/ml bovine serum albumin (IgG-free and protease-free) and 0,05% Sodium azide.

For most fluorescent streptavidin applications, a concentration of 1 to 10 mg/ml is sufficient; however, optimal conditions should be determined empirically.