Tetramethylrhodamine (TAMRA) is a fluorescent dye that has been popularly used for labeling oligonucleotides. Because of its instability to ammonium hydroxide, TAMRA was first used as TAMRA NHS Ester to label amino-modified oligonucleotides. However, later work showed that TAMRA is stable to UltraMild deprotection and also deprotection with hindered amines, like t-buylamine, so supports and phosphoramidites containing TAMRA were quickly introduced. TAMRA-modified oligonucleotides have established an important role in both Förster resonance energy transfer (FRET) and real-time PCR applications.
The spectral characteristics of these dyes are detailed here.
Carboxytetramethylrhodamine, N-hydroxysuccinimide ester in dimethyl sulfoxide (DMSO)
1-Dimethoxytrityloxy-3-[O-(N-carboxy-(Tetramethyl-rhodamine)-3-aminopropyl)]-propyl-2-O-succinoyl-long chain alkylamino-CPG