AFDye 488 Maleimide

Catalog#: 1014-1
Unit size: 1 mg
In stock
Catalog#: 1014-5
Unit size: 5 mg
In stock
Catalog#: 1014-25
Unit size: 25 mg
In stock
Catalog#: 1014-100
Unit size: 100 mg
In stock

AFDye™ 488 (Alexa Fluor® 488 equivalent) is a water-soluble, highly photostable dye with a very high fluorescence quantum yield. AFDye™ 488 has green fluorescence that is pH independent from pH 4 to pH 10 with excitation ideally suited for the 488 nm laser line. Its green fluorescence is pH independent from pH 4 to pH 10. AFDye™ 488 dye can be conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates which are often used for generation of stable signals in imaging and flow cytometry.

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.

AFDye™ 488 Maleimide dye is structurally identical to Invitrogen’s Alexa Fluor® 488 C5 Maleimide dye.

Thiol (Cys)
Abs/Em Maxima
493/516 nm
Extinction coefficient
72,000 cm-1M-1
Water, DMSO, DMF
Spectrally similar dyes
Alexa Fluor® 488, DyLight® 488, Fluorescein, Oregon Green 488
Molecular weight
698.67 (protonated)
Storage conditions
Shipping conditions
Ambient temperature

Enter only one — either volume or amount of protein to be labeled
Enter only one — either maximum concentration of DMSO or volume DMSO added to label

Alexa Fluor® is a registered trademark of Invitrogen, part of Thermo Fisher Scientific. Fluoroprobes is not affiliated with or endorsed by Thermo Fisher Scientific. AFDyes™ are GENERIC versions of Alexa Fluor® Dyes and ARE NOT manufactured, distributed, or affiliated in any way with Thermo Fisher Scientific.