Linear epitope

A linear epitope is an epitope that is recognized by antibodies by its linear sequence of amino acids, or primary structure. In contrast, most antibodies recognize an epitope that has a specific three-dimensional shape and its protein structure.

While performing molecular assays involving use of antibodies such as in Western blot, immunohistochemistry, ELISA, and others, care is taken into choosing antibodies that recognize linear or conformational epitopes.

For instance, if a protein sample is boiled, treated with beta-mercaptoethanol, and run in SDS-PAGE for Western blot, the proteins are essentially denatured and therefore cannot assume its natural three-dimensional conformation. Therefore antibodies that recognize linear epitope instead of conformational epitope are chosen for immunodetection. In contrast, in immunohistochemistry in which protein structure is preserved, antibodies that recognize conformational epitope is preferred.