Horseradish Peroxidase (HRP)

Need multiple seats for your university or lab? Get a quote
The page below is a sample from the LabCE course Immunohistochemistry (IHC) Basics in Histology. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Immunohistochemistry (IHC) Basics in Histology (online CE course)
Horseradish Peroxidase (HRP)

Horseradish peroxidase (HRP) is the most widely used enzyme for IHC labeling. The mechanism of HRP is such that an enzyme substrate complex is formed between HRP and excess hydrogen peroxide (H2O2). In the presence of a chromogen, the oxidized product of this reaction polymerizes to yield a color specific to the chromogen itself.
Commonly used chromogens with HRP include:
  • 3-amino-9-ethylcarbazole (AEC)
  • 3,3’-diaminobenzidine (DAB)