In immunohistochemistry (IHC), HRP is often conjugated to antibodies to detect specific antigens in tissue sections. The enzyme-antibody conjugate binds to the antigen, and the enzyme reacts with a chromogenic substrate, resulting in a colored precipitate at the site of the antigen. This enables the visualization of the antigen under a microscope. Common substrates include DAB (3,3'-diaminobenzidine) and AEC (3-amino-9-ethylcarbazole).
