Atto 665 maleimide

≥90% (coupling to thiols)


Quality Level


≥90% (coupling to thiols)

mol wt

Mw 845 g/mol


λex 663 nm; λem 684 nm in 0.1 M phosphate pH 7.0

storage temp.


General description

Atto 665 is a new fluorescent label closely related to Atto 647N. It shows extraordinary high fluorescence quantum yield, excellent thermal and photo-stability, outstanding ozone resistance, and very little triplet formation. Atto 665 is a cationic (charge +1). The dye is moderately hydrophilic. The maleimide of the dye is suitable for labeling sulfhydryl (thiol) groups of proteins, in particular. Cystein residues. Prepare labeling solution of maleimide-derivative immediately before use by dissolving the vial content in anhydrous and amine-free DMF or DMSO.

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Legal Information

This product is for Research use only. In case of intended commercialization, please contact the IP-holder (ATTO-TEC GmbH, Germany) for licensing.


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Atto dyes are a series of fluorescent dyes that meet the critical needs of modern fluorescent technologies.
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