5(6) cr110, se [5 (and 6) carboxyrhodamine 110, succinimidyl ester] *mixed isomers*

5(6)-CR110, SE [5-(and 6)-Carboxyrhodamine 110, succinimidyl ester] *Mixed isomers* is a Fluorescein for peptide and oligonucleotide labeling. Compared to fluorescein labeling reagents such as FITC and FAM, CR110 reagents give more photostable and pH-independent bioconjugates that have the absorption maximum around the preferred 488 nm excitation wavelength. They are photostable alternative reagents superior to FITC and FAM.