IR 680LT NHS ester (FP-1526)


IR 680LT (IRDye® 680LT equivalent) is a bright, water-soluble dye that is structurally very similar to the commonly used Cy®5.5 Dye. The water solubility, brightness, and self-quenching characteristics of this dye were significantly improved by the introduction of two additional sulfo groups. Far-red fluorescent IR 680 conjugates are spectrally similar to other 680 nm dyes that are used for flow cytometry, microscopy and other applications. Proteins can be labeled with IR 680 at high molar ratios without significant self - quenching, leading to brighter conjugates and more sensitive detection.

The NHS ester (succinimidyl ester) is the most popular tool for conjugating this dye to a protein or antibody. NHS esters can be used to label to the primary amines of proteins (Lys), amine-modified oligonucleotides, and other amine-containing molecules.


Unit Size1 mg, 5 mg, 25 mg, 100 mg
ReactivityPrimary amine
Abs/Em Maxima675/694 nm
Extinction coefficient190,000 cm-1M-1
SolubilityWater, DMSO, DMF
Spectrally similar dyesAlexa Fluor® 680, DyLight® 680, IRDye® 680
Molecular weight1320.46
Storage Conditions-20°C.
Shipping ConditionsAmbient temperature

Abs/Em Spectra

Protein Labeling Calculator


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