Although the mixed isomers of 5(6)-TAMRA Acid is a preferred, routinely used orange-fluorescent dye for staining proteins, it is rearly used for labeling peptides and nucleotides. 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.
The NHS Ester reacts specifically and efficiently with a primary amine (e.g., side chain of lysine residues or aminosilane-coated surfaces) at pH 7-9 to form a stable, covalent amide bond. The NHS ester (or succinimidyl ester) is the most popular tool for conjugating dyes to the primary amines of protein or antibody (Lys), amine-modified oligonucleotides, and other amine-containing molecules.