5-Carboxyrhodamine 110 NHS Ester (also known as Rhodamine Green™ Carboxylic Acid, Succinimidyl Ester, Hydrochloride or 5-CR 110, SE) is the nonsulfonated analog of the Alexa Fluor® 488 dye. The amine-reactive 5(6)-Carboxyrhodamine 110 NHS Ester can be used to create bright and photostable green-fluorescent bioconjugates with excitation/emission maxima ~502/527 nm. For many applications, the dye is preferred over 5-(6)-carboxyfluorescein NHS ester or FITC because of its exceptional photostability and fluorescence insensitivity to pH (4-9).
Although the mixed isomers of Carboxyrhodamine 110 NHS Ester preferred, routinely used fluorescent dye for labeling proteins, peptides and nucleotides, purification of peptide and nucleotides labeled with 5(6) isomers might be troublesome due to significant signal broadening in HPLC purification. Peptides and nucleotides labeled with a single isomer usually give better resolution in HPLC purification that is often required in the conjugation processes.