Although the mixed isomers of 5(6)-TAMRA Acid is a preferred, routinely used red fluorescent dye for staining proteins, labeling peptides and nucleotides, the purification of 5(6)-TAMRA labeled peptide and nucleotides might be troublesome due to significant signal broadening in HPLC purification. Peptides and nucleotides labeled with a single isomer TAMRA usually give better resolution in HPLC purification that is often required in the conjugation processes. 5-TAMRA is more often used for labeling peptides and proteins. 6-TAMRA is predominately used for labeling nucleotides and sequencing nucleic acids. 5-TAMRA dye is a bright fluorescent label is compatible with various excitation sources including mercury arc, tungsten and xenon arc lamps, the 544 nm line of the Helium-Neon laser and the 532 nm green laser line.