maleimidebiotin

Maleimidebiotin is a heterobifunctional bioconjugation reagent that combines a maleimide group with a biotin moiety. The maleimide component reacts selectively and covalently with thiol groups on cysteine residues to form stable thioether bonds, enabling attachment to proteins, peptides, or other thiol-containing targets. The biotin portion provides a high-affinity handle for detection, purification, or immobilization via interaction with streptavidin or avidin.

In practice, maleimidebiotin is used to label reduced or engineered thiols under mild conditions. Linkers between the maleimide and biotin can be short alkyl chains or polyethylene glycol (PEG) spacers, which modulate solubility and the accessibility of reactive groups. The resulting biotinylated conjugates can be captured or detected using streptavidin-based platforms, including affinity purification, ELISA, Western blotting, and various biosensor assays.

Commercial forms of maleimidebiotin vary by linker length and composition, but all retain the common feature of a thiol-reactive maleimide and a biotin tag. Handling typically requires standard precautions for reactive electrophiles and biotin-containing compounds, with attention to maintaining thiol integrity (often near neutral pH) to maximize labeling efficiency and minimize maleimide hydrolysis.

Maleimidebiotin is widely used in proteomics, bioconjugation, and bioassays to enable selective thiol labeling with convenient downstream biotin-based detection and purification.