MB™ 488 is a very hydrophilic, water-soluble green emitting dye. Structurally related to Alexa Fluor® 488 dye, MB™ 488 dye contains an additional, negatively charged sulfo group (SO3H) to improve water solubility and minimize self-quenching. Characteristic features of the label are strong absorption, high fluorescence quantum yield, and very high photostability. MB™ 488 is a highly suitable dye for single-molecule detection applications and high-resolution microscopy such as PALM, dSTORM, STED etc. Additionally MB™ 488 is an excellent dye for flow cytometry (FACS), fluorescence in-situ hybridization (FISH) and many other applications.
Maleimide is the most popular sulfhydryl-reactive reactive group for conjugating the dye to 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 bond. The resulting conjugates exhibit brighter fluorescence and greater photostability than the conjugates of many other spectrally similar fluorophores.