Product number: AF-0101

5/6-Carboxyfluorescein NHS ester, mixed isomers (5/6-FAM-SE)

Amine-reactive fluorescein dye marker for labeling of biomolecules (Abs: 496 nm, Em: 517 nm).

This item is not on stock and has to be re-ordered.

CAS-Number:	117548-22-8
Molecular Weight:	473,39
Empirical Formula:	C₂₅H₁₅NO₉
Absorption [nm]:	496 ± 3
Emission [nm]:	517 ± 3
ε [M-1 cm-1]:	>70 000
Excitation [nm]:	493 ± 3
Excitation source:	488 nm (Ar-Ion-Laser)
Buffer System for Fluorescence Readings:	T&S Buffer, pH 9
Solubility:	Acetonitrile, Acetone
Appearance (colour):	yellow orange
Appearance (form):	solid (powder)
Storage:	- 20 °C. Keep dry! Keep away from light, especially in solution!
Trade name:	5/6-Carboxyfluorescein-NHS-ester; 5/6-FAM-SE; 5-(and 6)-carboxyfluorescein succinimidyl ester, mixed isomers
Reactive Moiety:	NHS ester, reacts with 1° amines to form a stable amide linkage
Application:	labeling of antibodies, detection of proteins in cast gels and western blots (source: ThermoFisher Scientific - rephrase!)

This amine-reactive fluorescein derivatization reagent is widely used for covalent labeling of proteins and alkylamino modified nucleic acids.

Fluorescein has an excitation maximum that closely matches the 488 nm spectral line of the argon-ion laser, making it the predominant fluorophore for confocal laser scanning microscopy and flow cytometry applications. It has a relatively high absorptivity, excellent fluorescence quantum yield, and good water solubility.

Importantly, protein-fluorescein conjugates are not inordinately susceptible to precipitation.