Janelia Fluor^® 646, free acid

Biological Activity

Application: Suitable for flow cytometry, confocal microscopy, super resolution microscopy (SRM) including dSTORM (in both live and fixed cells) and STED. Used in protocol (2017 Grimm et al - see references below) for the synthesis of Janelia Fluor^® HaloTag^® and SNAP-Tag^® ligands, for use in live cell imaging experiments. Cell permeable.

Properties and Photophysical Data: Excitation and emission maxima (λ) are 646 nm and 664 nm, respectively; quantum yield = 0.54; extinction coefficient = 152,000 M^-1cm^-1. A280 correction factor = 0.19; lactone-zwitterion equilibrium constant (K_L-Z) = 0.0012.

To measure the absorbance spectrum of this dye we recommend the following solvent: ethanol or trifluoroethanol plus 0.1% TFA.

We also offer Janelia Fluor^® conjugated antibodies and custom conjugation services with our sister company Novus Biologicals.

HaloTag is a trademark of Promega Corporation, and SNAP-tag is a trademark of New England BioLabs, Inc.

Janelia Fluor is a registered trademark of Howard Hughes Medical Institute.

Optical Data for Janelia Fluor^® 646, free acid

Emission Color	Red
Brightness
λabs	646 nm
λem	664 nm
Extinction Coefficient (ε)	152,000 M-1cm-1
Quantum Yield (φ)	0.54
Closest Laser line	640 nm
Reactive Group	Free acid
Reactivity	Primary amines
Cell Permeable	Yes
Correction Factor 280	0.19
Application	Flow Cytometry, Confocal Microscopy, dSTORM, STED, Live-cell Imaging
Alternative For	Alexa Fluor® 647, Atto 647, Atto 647N, CF640R, CF647, Cyanine 5

Technical Data

The technical data provided above is for guidance only. For batch specific data refer to the Certificate of Analysis.
Tocris products are intended for laboratory research use only, unless stated otherwise.

Additional Information

Background References

1. A general method to improve fluorophores for live-cell and single-molecule microscopy.
   Grimm et al.
   Nat.Methods, 2015;12:244
2. Synthesis of Janelia Fluor HaloTag and SNAP-Tag Ligands and Their Use in Cellular Imaging Experiments.
   Grimm et al.
   Methods Mol.Biol., 2017;1663:179
3. Rational design of fluorogenic and spontaneously blinking labels for super-resolution imaging.
   Zheng et al.
   ACS Cent.Sci., 2019;5:1602

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