Peroxidase substrate

Peroxidase substrates are a diverse group of chemical compounds that act as electron donors in reactions catalyzed by peroxidase enzymes, such as horseradish peroxidase (HRP), myeloperoxidase (MPO), and thyroid peroxidase (TPO) (NIH, 2026). In these reactions, the enzyme utilizes hydrogen peroxide to oxidize the substrate, a process essential for biological functions like thyroid hormone synthesis (using iodide) and innate immune defense (using thiocyanate) (PubMed, 2013). In laboratory and diagnostic settings, synthetic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) and 3,3'-diaminobenzidine (DAB) are widely employed in ELISA and immunohistochemistry to generate colorimetric or fluorescent signals (Sigma-Aldrich, 2026). While critical for biochemical assays and certain physiological pathways, 'peroxidase substrates' refers to a functional class of molecules rather than a specific therapeutic protein target (ResearchGate, 2026). Some substrates can be bioactivated into reactive radicals, contributing to drug-induced toxicity or oxidative stress-related pathologies (NIH, 2022).

Other names

Chromogenic peroxidase substratesFluorogenic peroxidase substratesChemiluminescent peroxidase substratesHRP substratesElectron donors for peroxidases

Peroxidase substrates act as electron donors that are oxidized by peroxidase enzymes in the presence of hydrogen peroxide to produce reactive intermediates or detectable signals (NIH, 2026; PubMed, 2013).