6-Carboxyfluorescein

6-Carboxyfluorescein (6-FAM) is a fluorescent dye with an absorption wavelength of 495 nm and an emission wavelength of 517 nm. A carboxyfluorescein molecule is a fluorescein molecule with a carboxyl group added. They are commonly used as a tracer agents. It is used in the sequencing of nucleic acids and in the labeling of nucleotides.

Quick facts Names, Identifiers ...

6-Carboxyfluorescein

Names
Other names 6-FAM
Identifiers
CAS Number	3301-79-9 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:39073 Y
ChEMBL	ChEMBL1614944
ChemSpider	69262 Y
ECHA InfoCard	100.164.295
PubChem CID	76806
UNII	JHJ853P6SM Y
CompTox Dashboard (EPA)	DTXSID6062965
InChI InChI=1S/C21H12O7/c22-11-2-5-14-17(8-11)27-18-9-12(23)3-6-15(18)21(14)16-7-10(19(24)25)1-4-13(16)20(26)28-21/h1-9,22-23H,(H,24,25) Y Key: BZTDTCNHAFUJOG-UHFFFAOYSA-N Y InChI=1/C21H12O7/c22-11-2-5-14-17(8-11)27-18-9-12(23)3-6-15(18)21(14)16-7-10(19(24)25)1-4-13(16)20(26)28-21/h1-9,22-23H,(H,24,25) Key: BZTDTCNHAFUJOG-UHFFFAOYAC
SMILES C12C=CC(=O)C=C1Oc3cc(O)ccc3C=2c4cc(C(O)=O)ccc4C(O)=O
Properties
Chemical formula	C21H12O7
Molar mass	376.320 g·mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P305+P351+P338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

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Commercially available FAM is a mixture of two isomers, 5-FAM and 6-FAM, and the correct name is 5(6)-carboxyfluorescein.

The dyes are membrane-impermeant and can be loaded into cells by microinjection or scrape loading.^[1] It can be incorporated into liposomes, and allows for the tracking of liposomes as they pass through the body. In addition, carboxyfluorescein has been used to track division of cells.^[2] In vascular plants, 5(6)-carboxyfluorescein can be used as a symplastic tracer. It is able to move through the phloem due to its structural similarity to sucrose.^[3] It is typically loaded into the leaves in order to gain access to the phloem.^[4][5] This can be done by scraping, cutting, or weakening the leaf’s cuticle with an herbicide.

Popular derivatives for cell tracing purposes are carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and carboxyfluorescein succinimidyl ester (CFSE).