Biotinylation

Biotinylation is the process of covalently binding biotin to a molecule, usually a protein or DNA. This occurs in some proteins as post-translational modification. Biotinylation is used specifically in the laboratory in order to (for example, upon detection by ELISA, ELISPOT, Western blot and immunohistochemistry ) to tag a molecule for the purposes of a molecular tag or purification. Then made ​​of the strong specific interaction between biotin and avidin or streptavidin advantage.

Application Examples

Biotinylation can be artificially introduced into the molecules, such as in vivo. By protein tags such Avi-tag, BCCP tag, Strep-tag or in vitro by coupling with reactive biotins such as NHS -biotin

Biotinylation can be used (eg, nucleic acids) for the purification of biotin - labeled substances. This gives you the biotin - labeled target substance to a affinity chromatography columns whose column material carrying covalently bound avidin. The biotin binds to the avidin, and then rinsed the surface so that non-bound substances are washed away. The biotinylated molecules can then also disconnect by appropriate biotin - containing or denaturing elution from the surface.

Coupling with biotin is also used for marking of certain molecules (e.g., protein). In some cases, the detected molecules are biotinylated directly and can for example be made visible using an avidin -coupled dye. Often, however, is forfeited to the signal strength on direct detection and inserted a series of intermediate reactions. This additionally has the advantage that for the detection of different molecules for the most part the same range of materials can be used - only the first substance (often antibodies) that specifically binds to the target must be replaced.