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Peroxidase from horseradish

Type VI, essentially salt-free, lyophilized powder, ≥250 units/mg solid (using pyrogallol)

Detection Enzyme, HRP, Peroxidase, Donor:hydrogen-peroxide oxidoreductase, Horseradish peroxidase
CAS Number:
Enzyme Commission number:
Numéro EC:
Numéro MDL:


Type VI

Niveau de qualité



essentially salt-free, lyophilized powder

specific activity

≥250 units/mg solid (using pyrogallol)

Poids mol.

~44 kDa


0.1 M phosphate buffer: soluble 10 mg/mL, clear, orange to red (pH 6.0)

Rapport des absorbances

RZ 2.5-4.0


diagnostic assay manufacturing

Temp. de stockage


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Description générale

Horseradish peroxidase is isolated from horseradish roots (Amoracia rusticana) and belongs to the ferroprotoporphyrin group of peroxidases. HRP is a single chain polypeptide containing four disulfide bridges. It is a glycoprotein containing 18% carbohydrate. The carbohydrate composition consists of galactose, arabinose, xylose, fucose, mannose, mannosamine, and galactosamine depending upon the specific isozyme. Its molecular weight (~44 kDa) includes the polypeptide chain (33,890 Daltons), hemin plus Ca2+ (~700 Daltons), and carbohydrate (~9,400 Daltons). At least seven isozymes of HRP exist. The isoelectric point for horseradish peroxidase isozymes ranges from 3.0 - 9.0.


Horseradish peroxidase (HRP) is isolated from horseradish roots (Amoracia rusticana) and belongs to the ferroprotoporphyrin group of peroxidases.. It is used in biochemistry applications such as western blots, ELISA and Immunohistochemistry. Horseradish peroxidase is used to amplify a weak signal and increase detectability of a target molecule, such as a protein. Product P8375, type VI, is an essentially salt free lyophilized powder. It is commonly used to determine amounts of glucose and peroxides in solution. It has been used to study sensory input of cervical spinal cord neurons.
The enzyme has been used to develop a thermostable soybean peroxidase-based biosensor by cross-linking and electrically ′wiring′ the enzyme through a redox-conducting hydrogel to a glassy carbon electrode. It has also been used to assay the oxidation of low density lipoprotein.


1000, 2000 units in glass bottle
5000 units in poly bottle
10000, 25000, 100000, 250000 units in glass bottle

Actions biochimiques/physiologiques

HRP readily combines with hydrogen peroxide (H2O2) and the resultant [HRP-H2O2] complex can oxidize a wide variety of hydrogen donors. The optimal pH is 6.0-6.5 and the enzyme is most stable in the pH range of 5.0-9.0. HRP can be conjugated to antibodies by several different methods including glutaraldehyde, periodate oxidation, through disulfide bonds, and also via amino and thiol directed cross-linkers. It is smaller and more stable than the enzyme labels β-galactosidase and alkaline phosphatase and hence, it is the most desired label. Also, its glycosylation leads to lower non-specific binding.
When incubated with a substrate, horseradish peroxidase produces a coloured, fluorimetric, or luminescent derivative of the labeled molecule, allowing quantification. Horseradish peroxidase has been shown to slightly reduce the level of inhibition in a cydAB mutant. Known inhibitors are sodium azide, cyanide, L-cystine, dichromate, ethylenethiourea, hydroxylamine, sulfide, vanadate, p-aminobenzoic acid, and Cd2+, Co2+, Cu2+, Fe3+, Mn2+, Ni2+, and Pb2+ ions.

Définition de l'unité

One pyrogallol unit will form 1.0 mg purpurogallin from pyrogallol in 20 sec at pH 6.0 at 20 °C.

Remarque sur l'analyse

The RZ (Reinheitszahl) is the absorbance ratio A403/A275 determined at 0.5-1.0 mg/ml in deionized water. It is a measure of hemin content, not enzymatic activity. Even preparations with high RZ may have low enzymatic activity.

Autres remarques

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Health hazard

Mention d'avertissement


Mentions de danger

Classification des risques

Resp. Sens. 1 - Skin Sens. 1

Code de la classe de stockage

11 - Combustible Solids



Équipement de protection individuelle

Eyeshields, Gloves, type N95 (US)

Certificate of Analysis

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Certificate of Origin

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