CAS 76823-03-5: 5-carboxyfluorescein

5-FAM, a carboxylic acid, reacts with amines for biomolecule labeling; excites at 488 nm, high fluorescence, solubility, absorbance.

5-Carboxyfluorescein (5-FAM) is a self-quenching dye and one of the most common labelling agents for biomolecules, cell staining and localisation studies. The fluorescence is pH dependent, therefore it has been used to measure the internal pH of cells. As it is only membrane permeable to dead cells, it can be used as a staining agent to distinguish viable and non-viable cells. It is also used in PCR to label the 5’ end of oligonucleotides in the presence of a quencher at the 3’ end (dual labelled probe). During the amplification process, the dye is cleaved and the fluorescence increases proportionally with the amount of the specific sequence amplified during the PCR process. The development of the fluorescence signal is therefore specifically related to the amplification of the target sequence. The carboxylic acid can be activated to react with a primary amine.

This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.

5-FAM

Applications 5-Carboxyfluorescein is a useful reagent for the preparation of hydrolytically stable fluorescent conjugates and is a useful starting material for the synthesis of other fluorescein-derives reagent. Dyes and metabolites. References Theisen, P., et al.: Tetrahedron Lett., 33, 5033 (1992); Mattingly, P.: Bioconjgate Chem., 3, 430 (1992); Bertrand, R., et al.: Biochemistry, 34, 9500 (1995);

5-Carboxyfluorescein

This Thermo Scientific Chemicals brand product was originally part of the Acros Organics product portfolio. Some documentation and label information may refer to the legacy brand. The original Acros Organics product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.

Widely used green-fluorescent labeling dye.