Biotin-X-maleimide is a thiol-reactive bifunctional linker for labeling SH groups. It can be used to attach biotin to proteins and peptides via cysteine residues and to other thiolated molecules, such as thiol-containing oligonucleotides.
Biotin-labeled compounds can then be linked to avidin or streptavidin for further purification or detection. The biotin group is relatively small and doesn’t affect the biological activity of biotinylated molecules.
The reagent contains an aminocaproic spacer arm that relieves steric hindrance for binding the target molecule to streptavidin and avidin.