Fluorescein Maleimide is designed for fluoresceinating proteins, nucleic acids or other molecules containing one or more thiol groups. Molecules to be labeled with Fluorescein Maleimide require free thiol groups. In the case of proteins, Fluorescein Maleimide will react with exposed cysteine residues. Alternatively, free thiols may be generated by reducing disulfide bonds or by modifying other reactive groups such as primary amines with compounds like Traut's reagent (2-iminothiolane).

This fluorescent label can be directly detected or used as a hapten and detected with our high affinity antibody reagents. (Excitation maximum at 495 nm; emission maximum at 515 nm).