We developed biotin-rhodamine 110 as an alternative to biotin-4-fluorescein (90062) and fluorescein biotin (80019), both of which have been used for detection of biotin binding sites and the degree of biotinylation of proteins, and for the measurement of avidin and streptavidin in crude biological samples. In addition, biotin-rhodamine 110 can be used as a polar tracer to study the morphology of cells, similar to the use of Lucifer Yellow cadaverine biotin-X has absorption and emission wavelengths similar to those of fluorescein. However, the spectra and fluorescent quantum yield of rhodamine 110 are relatively unaffected by pH (pH 4-9), whereas the fluorescence of fluorescein is significantly reduced at acidic pH. Moreover, rhodamine 110 is much more photostable than fluorescein, making biotin-rhodamine 110 a better choice for studies where prolonged exposure to light may be necessary. Also see our CF® Dye Biotin conjugates, with superior brightness and photostability.    &lamba;Ex/&lamba;Em (MeOH) = 502/524 nm  Orange red solid soluble in DMF or DMSO  Store at 4°C and protect from light, especially in solution  C41H50N6O9S  MW: 802.94