CyT2 Streptavidin, 1 mg

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: Cyanine Cy™2 Cy2 conjugates have maximum absorption/excitation at 492 nm and fluoresce with a peak around 510 nm in the green region of the visible spectrum like FITC conjugates (520 nm), but they are more photostable and less sensitive to pH changes than FITC. However, for mounting in aqueous media we recommend Alexa Fluor® 488 as the preferred green-fluorescing dye because it is brighter and more photostable than Cy2, FITC, and DyLight 488. A further disadvantage of using Cy2 with aqueous mounting media is its sensitivity to p-phenylenediamine, an anti-fading agent found in some commercial mounting media, which results in weak and diffused fluorescence after storage of stained slides. The main advantage of Cy2 conjugates is increased fluorescence in plastic mounting media.