ABSTRACT
Enzyme-Linked ImmunoabSorption Assay, or “ELISA”, allows an enzyme that can be monitored to indicate the presence of a non-enzymatic protein that cannot. An immunoglobin antibody binds to some epitope on the target protein. An epitope is just some feature on the surface which is recognized by the immunoglobin. Blocking merely means saturating the surface with something else that the antibody will not bind to. Some of the target protein can be displaced by the blocking reagent, especially if the target protein is small and has less surface area. Experimental considerations include the need to get the protein of interest to adhere to the walls of the reaction chamber. Microwells of polystyrene are usually used, because most proteins bind with some affinity to the polystyrene. Common and inexpensive proteins can be added in great abundance to saturate the polystyrene walls.
