The non-activated carboxytetramethyl rhodamine derivative is used as a red fluorescent derivatization reagent for covalently labeling proteins and alkylamino modified nucleic acids. It contains a three carbon amino-functionalized linker for conjugation with activated carboxyl groups or other amine-reactive moieties.
The fluorescence quantum yield of TAMRA conjugates is about one-fourth that of fluorescein conjugates. Nevertheless, TAMRA conjugates often appear brighter than the corresponding fluorescein conjugates due to the fact that TAMRA is readily excited by the 546 nm spectral line from mercury-arc lamps used in most fluorescence microscopes and is intrinsically more photostable than fluorescein. TAMRA is also efficiently excited by the 543 nm spectral line of the green He-Ne laser.
