Steptavidin, a bacterial protein isolated from Streptomyces avidinii, is similar to egg-white avidin in its ability to bind biotin, and has been used as a replacement for egg-white avidin because of its more favorable chemical properties.
Conjugates of streptavidin are recommended for use with Biotin-SP-conjugated antibodies and Biotin-SP-conjugated ChromPure proteins.
Conjugate: R-Phycoerythrin
Phycoerythrin (R-PE) is among several kinds of light-harvesting phycobiliproteins found in red, blue-green, and cryptomonad algae. We offer R-PE, the form found in red macrophytic algae (seaweed). After phycobiliproteins are conjugated to secondary antibodies, there is little fluorescence quenching, which results in conjugates of high specific fluorescence compared with conventional fluorophore-antibody conjugates. R-PE can be excited by light over a wide range of the visible spectrum is highly water soluble, has a relatively low isoelectric point, and lacks potentially sticky carbohydrates.
It should be noted that the relatively high molecular weight of R-PE may preclude its use in procedures requiring good penetration into cells and tissues. It is predominantly intended for surface labeling of cells for flow cytometry.