Use of Strept avidin-Biotin Interactions in Assay Systems

Use of (Strept)avidin—Biotin Interactions in Assay Systems 

A common application for (strept)avidin-biotin chemistry is in immunoassays. The specificity of antibody molecules provides the targeting capability to recognize and bind particular antigen molecules. If there are biotin labels on the antibody, it creates multiple sites for the binding of (strept)avidin. If (strept)avidin is in turn labeled with an enzyme, fluorophore, etc., then a very sensitive antigen detection system is created. The potential for more than one labeled (strept)avidin to become attached to each antibody through its multiple biotinylation sites is the key to dramatic increases in assay sensitivity over that obtained through the use of antibodies directly labeled with a detectable tag. 

Similar techniques can be used to devise (strept)avidin-biotin assay systems for detection of nucleic acid hybridization. DNA probes labeled with biotin can be detected after they bind 

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