Several substrates are commonly used with HRP in histological staining:
DAB (3,3'-diaminobenzidine): Produces a brown color and is often used for permanent mounting. AEC (3-amino-9-ethylcarbazole): Produces a red color but is less stable than DAB, making it suitable for short-term studies. Others: Substrates like TMB (3,3',5,5'-tetramethylbenzidine) and OPD (o-phenylenediamine) are also used but less frequently in histology.