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Janelia Fluor 646

Janelia Fluor® 646 (Ex-Max 646 nm/Em-Max 664 nm)

Janelia Fluor® 646 was developed at the Janelia Campus of the Howard Hughes Medical Institute but is commercialized by other vendors. The Janelia Fluor®s family is unique in that the fluorophores are cell-permeable and are available in photoactivatable forms. These fluorophores were developed for super-resolution microscopy (STED, PALM and STORM) and live-cell microscopy in the HaloTag and SNAP-tag versions. Janelia Fluor® 646 has an excitation peak at 646 nm and an emission peak at 664 nm.

Excitation & emission spectra

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Key facts

Excitation maximum
646 nm
Emission maximum
664 nm
Optimal laser line
628-640
Optimal filter
660/20
Relative brightness
4 of 5
Extinction coefficient
152000
Quantum yield
0.54
Commercial conjugates
2.5k from 1 supplier

Janelia Fluor 646 has an excitation maximum at 646 nm and an emission maximum at 664 nm, a Stokes shift of 18 nm. Its extinction coefficient is 152000 M⁻¹cm⁻¹. It is optimally excited by the 628-640 laser line.

Frequently asked questions

What is Janelia Fluor 646?
Janelia Fluor® 646 was developed at the Janelia Campus of the Howard Hughes Medical Institute but is commercialized by other vendors. The Janelia Fluor®s family is unique in that the fluorophores are cell-permeable and are available in photoactivatable forms. These fluorophores were developed for super-resolution microscopy (STED, PALM and STORM) and live-cell microscopy in the HaloTag and SNAP-tag versions. Janelia Fluor® 646 has an excitation peak at 646 nm and an emission peak at 664 nm.
What laser excites Janelia Fluor 646?
Janelia Fluor 646 is optimally excited by the 628-640 laser line. Its excitation maximum is 646 nm.
What filter should I use to detect Janelia Fluor 646?
A 660/20 filter captures the peak of the Janelia Fluor 646 emission near 664 nm with minimal spillover.
How bright is Janelia Fluor 646?
Janelia Fluor 646 has a relative brightness of 4 out of 5 (quantum yield 0.54).
How many antibodies are available conjugated to Janelia Fluor 646?
FluoroFinder tracks 2459 commercially available Janelia Fluor 646 conjugates, searchable by target, clone, host and application.