Biotinylation is the process of adding a Biotin tag to a molecule or surface.

Purpose

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Purification

The biotin tag can be used in affinity chromatography together with a column that has avidin or streptavidine bound to it, which is the natural chelator for biotin.

Detection

This tag can also be used in detection of the protein via anti-biotin antibodies or avidine/streptavidine tagged detectors like horseradish peroxidase or a member of the green fluorescent protein family. This can be useful in localization, ELISA assays, ELISPOT assays, western blots and other immunoanalytical methods.

Other uses

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The non-covalent bond formed between biotin and avidin or streptavidin has a binding affinity that is tighter than most antigen and antibody bonds and approaches the strength of a covalent bond. This very tight binding makes labeling proteins with biotin a useful tool for applications such as affinity chromatography using immobilized avidin or streptavidin to separate the biotinylated protein from a mixture of other proteins and biochemicals. Biotinylated protein such as biotinylated bovine serum albumin (BSA) is used in solid-phase assays as a coating on the well surface in multiwell assay plates. Biotinylation of red blood cells has been used as a means of determining total blood volume without the use of radiolabels such as chromium 51, allowing volume determinations in low birth weight infants and pregnant women who could not otherwise be exposed to the required doses of radioactivity.

See also

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• nanotechnology

Posttranslational modification