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: PerCP
PerCP is a fluorescent peridinin-chlorophyll-protein complex isolated from dinoflagellates. We offer the form found in Dinophyceae sp. with a molecular weight of about 35.5 kDa. It has a broad spectrum of excitation with a main peak at 482 nm, and a long Stokes shift to an emission peak at 677 nm.
PerCP, Alexa Fluor® 488 (or FITC), and R-PE are excited at 488 nm with an argon laser, and thus can be used for one-, two-, and three-color analyses with single-laser flow cytometers. APC and Alexa Fluor® 647 are excited at 633 nm to give a fourth color with dual-laser flow cytometers.
PerCP is also 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 PerCP 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.