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Alexa Fluor 647

Alexa Fluor™ 647 (Ex-Max 650 nm/Em-Max 668 nm)

Alexa Fluor™ 647 (AF647, Alexa 647) has an excitation peak at 650 nm and an emission peak at 665 nm, and is spectrally similar to Cy®5 (GE Healthcare), iFluor® 647 (ATT Bioquest), and DyLight™ 650 (Thermo Fisher Scientific). Alexa 647 is commonly used for flow cytometry, microscopy, super-resolution microscopy applications. It is very bright, photostable, and pH insensitive, all of which contribute to sensitive detection while using this dye.

Excitation & emission spectra

400450500550600650700750800

Key facts

Excitation maximum
650 nm
Emission maximum
665 nm
Optimal laser line
628-640
Optimal filter
660/20
Relative brightness
4 of 5
Extinction coefficient
239000
Quantum yield
0.33
Molecular weight
800
Commercial conjugates
4.7k from 27 suppliers

Alexa Fluor 647 has an excitation maximum at 650 nm and an emission maximum at 665 nm, a Stokes shift of 15 nm. Its extinction coefficient is 239000 M⁻¹cm⁻¹. It is optimally excited by the 628-640 laser line.

Frequently asked questions

What is Alexa Fluor 647?
Alexa Fluor™ 647 (AF647, Alexa 647) has an excitation peak at 650 nm and an emission peak at 665 nm, and is spectrally similar to Cy®5 (GE Healthcare), iFluor® 647 (ATT Bioquest), and DyLight™ 650 (Thermo Fisher Scientific). Alexa 647 is commonly used for flow cytometry, microscopy, super-resolution microscopy applications. It is very bright, photostable, and pH insensitive, all of which contribute to sensitive detection while using this dye.
What laser excites Alexa Fluor 647?
Alexa Fluor 647 is optimally excited by the 628-640 laser line. Its excitation maximum is 650 nm.
What filter should I use to detect Alexa Fluor 647?
A 660/20 filter captures the peak of the Alexa Fluor 647 emission near 665 nm with minimal spillover.
How bright is Alexa Fluor 647?
Alexa Fluor 647 has a relative brightness of 4 out of 5 (quantum yield 0.33).
How many antibodies are available conjugated to Alexa Fluor 647?
FluoroFinder tracks 4722 commercially available Alexa Fluor 647 conjugates, searchable by target, clone, host and application.