5(6)-FAM [5-(and-6)-Carboxyfluorescein] (Validated for labeling peptides and oligos)

Carboxyfluorescein (commonly called FAM) and its amine-reactive succinimidyl esters are favored over FITC in bioconjugations. FAM reagents give carboxamides that are more resistant to hydrolysis. In addition, FAM reagents require less stringent conjugation conditions and give better conjugation yields, and the resulted conjugates have superior stability. FITC-labeled nucleotides and peptides tend to deteriorate more quickly than the corresponding FAM conjugates. We found that FAM reagents can be used to substitute FITC reagents in most biological applications.