AFDye 488 Maleimide

Unit Size
Price (USD)
1 mg
In stock
5 mg
In stock
25 mg
In stock
100 mg
In stock

    AFDye™ 488 Maleimide (Alexa Fluor® 488 C5 Maleimide equivalent) is a green-fluorescent, water-soluble dye with pH insensitive emission from pH 4 to pH 10. This dye is ideally suited to the 488 nm laser line. AFDye 488 is one of the brightest dyes commercially available with fluorescence quantum yield close to 100%.

    Maleimide is the most popular sulfhydryl-reactive reactive group for conjugating the dye to either a thiol group on a protein, oligonucleotide thiophosphate, or low molecular weight ligand. The maleimide group specifically and efficiently reacts with reduced thiols (sulfhydryl groups, –SH) at pH 6.5 to 7.5 to form stable thioether bonds. The resulting conjugates exhibit brighter fluorescence and greater photostability than the conjugates of many other spectrally similar fluorophores.

    Abs/Em Maxima
    494/517 nm
    Extinction Coefficient
    Flow Cytometry Laser Line
    488 nm
    Microscopy Laser Line
    488 nm
    Spectrally Similar Dyes
    FAM, Alexa Fluor® 488, Atto™ 488, CF® 488A Dye, DyLight® 488
    Molecular weight
    698.67 (protonated)
    Water, DMSO, DMF
    Orange to light red solid
    Storage conditions
    -20°C. Desiccate
    Shipping conditions
    Ambient temperature

    AFDye™ 488 Maleimide (Alexa Fluor® 488 C5 Maleimide equivalent) is a thio reactive, green emitting dye routinely used to label proteins or antibodies through the sulfhydryl groups (Cys), thoil-modified oligonucleotides, and other thiol-containing biomolecules. The labeling occurs most efficiently at pH 6.5-7.5 and forms a stable, covalent amide bond.

    AFDye™ 488 is a water-soluble, highly photostable dye with very high fluorescence quantum yield. Its green fluorescence is pH independent from pH 4 to pH 10. The excitation of AFDye™ ideally suited for the 488 nm line. AFDye™ 488 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates often used for generation of stable signal in imaging and flow cytometry.

    AFDye™ 488 is structurally identical to Alexa Fluor® 488. Its absorption/emission spectra is a perfect match to spectra of many other fluorescent dyes based on sulfonated rhodamine 110 core, including DyLight® 488, Alexa Fluor® 488. AFDye™ 488 Maleimide can be used a less expensive alternative to Alexa Fluor® 488 C5 Maleimide.

    DyLight® and Alexa Fluor® are a registered trademark of Thermo Fisher Scientific.


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