Biotin (Long Arm) Maleimide is designed for biotinylating proteins, nucleic acids or other molecules containing one or more thiol groups. The presence of the 6-aminohexanoate spacer arm between the maleimide group and biotin reduces the possibility of steric hinderance. Molecules to be labeled with Biotin (Long Arm) Maleimide require free thiol groups. In the case of proteins, Biotin (Long Arm) 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).

Biotin (Long Arm) Maleimide reacts readily under mild acid or neutral pH conditions in aqueous solution with free sulfhydryl groups such as cysteine residues or thiol groups introduced chemically into proteins, nucleic acids, or other macromolecules.

For labeling nucleic acids, thiols can be introduced into DNA, RNA, or oligonucleotides using the 5' EndTag™ or 3' EndTag™ nucleic acid labeling systems.

Because of the extraordinary affinity of avidin and streptavidin to biotin and the many biotin-avidin/streptavidin systems available, the biotin label is ideal for a variety of applications including in situ hybridization, blotting, and affinity binding.

The spacer arm in this derivative insures that the biotin is fully accessible to avidin or streptavidin detection systems.