• USA Home
  • P6782 - Peroxidase from horseradish

P6782 Sigma

Peroxidase from horseradish

Type VI-A, essentially salt-free, lyophilized powder, 950-2000 units/mg solid (using ABTS), 250-330 units/mg solid (using pyrogallol)

Synonym: Donor:hydrogen-peroxide oxidoreductase, Horseradish peroxidase



Analysis Note

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.

This product is assayed using ABTS for easy comparison to other suppliers′ unit: approx. 1,000 units per mg solid


Similar to P8375

Other Notes

View more information on peroxidase at www.sigma-aldrich.com/enzymeexplorer.


10, 25 mg in poly bottle

5 mg in glass bottle

Packaged in mg solid

50, 100 mg in glass bottle

Preparation Note

The product is a 1 mg/mL solution in 0.1 M phosphate buffer(pH 6.0) and remains active for at least two weeks at room temperature. The solution retains activity after 5 freeze-thaw cycles.

Unit Definition

One ABTS unit will oxidize 1 μmole of ABTS per minute at 25 °C at pH 5.0

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


Horseradish peroxidase (HRP) is isolated from horseradish roots (Amoracia rusticana). 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 P6782 is type VI-A and premium quailty. It is essentially a salt-free, lyophilized powder. It is used to quantify cholesterol and cholesterol esters1 and to study in vitro lipid deposition on hydrogel and silicone hydrogel contact lenses2.

The enzyme from Sigma has been used in the development of rapid and sensitive galactose oxidase-peroxidase biosensor for galactose detection with prolonged stability. It has been used as a component of a media (MRS agar) plate containing 3,3′,5,5′-tetramethylbenzidine (TMB) for the growth of Lactobacillus sp. TMB acts as a chromogenic substrate of peroxidase. Peroxidase generates O2 from H2O2 produced by the lactobacilli, and the TMB stains the colonies blue in the presence of O2. Thus, after 48 hours of incubation under 5% CO2 in air, the colonies that produce H2O2 on MRS agar appear dark blue. H2O2 nonproducers are colorless. It has been used to study the stabilization effect of polyvinyl alcohol on horseradish peroxidase. It is also used for the determination of glucose and peroxides in solution.

Biochem/physiol Actions

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 that include the use of glutaraldehyde, periodate oxidation, 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. Hence, it is the most desired label. Also, its glycosylation leads to lower non-specific binding.3 Sodium azide, cyanide, L-cystine, dichromate, ethylenethiourea, hydroxylamine, sulfide, vanadate, p-aminobenzoic acid, as well as Cd2+, Co2+, Cu2+, Fe3+, Mn2+, Ni2+, and Pb2+ ions are found to inhibit the enzyme activity.4

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.

General description

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.

Price and Availability

Suggested Laboratory Gloves

Laboratory GlovesThis substance has been tested against several types of hand protection for CE compliance. Click below to find the recommended gloves for handling this product.

Now Available! MSMLS™

Discover Your Pathway

Customers Also Viewed

Type VI, essentially salt-free, lyophilized powder, 250-330 units/mg solid (using pyrogallol)

lyophilized, powder, beige, ~150 U/mg

Type II, essentially salt-free, lyophilized powder, 150-250 units/mg solid (using pyrogallol)

Type I, essentially salt-free, lyophilized powder, 50-150 units/mg solid (using pyrogallol)

Type XII, essentially salt-free, lyophilized powder, 250-330 units/mg solid (using pyrogallol)

Safety & Documentation

Safety Information

WGK Germany 
Protocols & Articles


Antibody Basics

Immunoglobulins (Igs) are produced by B lymphocytes and secreted into plasma. The Ig molecule in monomeric form is a glycoprotein with a molecular weight of approximately 150 kDa that is shaped more ...
Keywords: Affinity chromatography, Centrifugation, Chromatography, Digestions, High performance liquid chromatography, Ion Exchange, Microscopy, Precipitation, Purification, Scanning electron microscopy


Enzymatic Assay of Peroxidase (EC 2,2'-Azino-bis(3-Ethylbenzthiazoline-6-Sulfonic Acid) as a Substrate

Replaces SPABTS02. Procedure updated to conform to current QUMAS formatting guidelines. Refer to CR SOP-DEK-ENZ42.
Keywords: Extinction coefficient

Enzymatic Assay of Peroxidase (EC

This procedure is for the determination of Peroxidase enzymatic activity using Pyrogallol as the substrate. Products using this method include, but are not limited to, P1709, P2088, P6140, P6782, P81...
Keywords: Enzymology, Extinction coefficient, Gene expression, Size-exclusion chromatography

Spectrophotometric Determination of Reinheitszahl (RZ) for Peroxidase (EC

Reinheitszahl (RZ) is the ratio of absorbance due to hemin (A403, Soret region) to absorbance due to protein (A275). This ratio (A403/A275) is not a measure of enzyme activity. Products using this me...

Related Content

Antibody Explorer - Over 80,000 Products

Monoclonal and polyclonal primary antibodies are focused on cell biology, neurobiology and molecular biology. Secondary antibodies targeting multiple host’s IgG are conjugated to alkaline phosphatase...
Keywords: Buffers, Cell biology, Enzyme-linked immunosorbent assay, Immunohistochemistry, Immunoprecipitation, Molecular biology, Peptide synthesis, Phosphorylations, Purification, Western blot

Enzyme Explorer: the most comprehensive source of enzymes, substrates, activators, & inhibitors.

Find enzymes / proteins, substrates, activators, and inhibitors. Resources for metabolic pathways, kinases, proteolytic enzymes and inhibitors, carbohydrate analysis as well as new cell signaling, an...
Keywords: Cell culture, Cell disruption, Cell signaling, Diagnostic, Digestions, Drug discovery, Functional genomics, Gene expression, Genomics, Metabolic Pathways, Molecular biology, Neuroscience, Proteomics

Peer-Reviewed Papers


Set your institution to view full text papers.

1. Enzymatic Quantification Of Cholesterol And Cholesterol Esters From Silicone Hydrogel Contact Lenses. Pucker, A.D., et al. Invest. Ophthalmol. Vis. Sci. 51, 2949-54, (2010)


2. In Vitro Lipid Deposition On Hydrogel And Silicone Hydrogel Contact Lenses. Pucker, A.D., et al. Invest. Ophthalmol. Vis. Sci. 51, 6334-40, (2010)


Rapid and sensitive galactose oxidase-peroxidase biosensor for galactose detection with prolonged stability Tkác J, et al. Biotechnol. Tech. 13(12), 931-936, (1999)

Stabilization effect of polyvinyl alcohol on horseradish peroxidase, glucose oxidase, β-galactosidase and alkaline phosphatase. Boyd S, et al. Biotechnol. Tech. 10(9), 693-698, (1996)

Lactobacillus species identification, H2O2 production, and antibiotic resistance and correlation with human clinical status. Felten A, Barreau C, Bizet C, et al. J. Clin. Microbiol. 37(3), 729-33, (1999)


Effects of high temperature on multiple parameters of broilers in vitro and in vivo. Feng, J., et al. Polymer 87, 2133-9, (2008)


The TL29 protein is lumen located, associated with PSII and not an ascorbate peroxidase. Granlund, I., et al. Plant Cell 50, 1898-910, (2009)


Rapid clearance of circulating protein by early chicken embryo blood cells. Wu, G., and Li, Z. J. Immunol. Methods 212, 2176-82, (2009)


2-carboxyquinoxalines kill mycobacterium tuberculosis through noncovalent inhibition of DprE1. Neres J, Hartkoorn RC, Chiarelli LR, et al. ACS Chem. Biol. 10(3), 705-14, (2015)


Epitope specificity determines pathogenicity and detectability in ANCA-associated vasculitis. Roth AJ, Ooi JD, Hess JJ, et al. J. Clin. Invest. 123(4), 1773-83, (2013)


Phage-type RNA polymerase RPOTmp performs gene-specific transcription in mitochondria of Arabidopsis thaliana. Kühn K Plant Cell 21(9), 2762-79, (2009)


RACK1 is a negative regulator of ABA responses in Arabidopsis. Guo J J. Exp. Bot. 60(13), 3819-33, (2009)


Arabidopsis TONNEAU1 proteins are essential for preprophase band formation and interact with centrin. Azimzadeh J Plant Cell 20(8), 2146-59, (2008)


Host responses to intestinal microbial antigens in gluten-sensitive mice. Jane M. Natividad et al PLoS ONE 4, e6472, (2009)


Assessment of myeloperoxidase activity by the conversion of hydroethidine to 2-chloroethidium. Maghzal GJ, Cergol KM, Shengule SR, et al. J. Biol. Chem. 289(9), 5580-95, (2014)


Design, synthesis, and structure-activity relationship studies of novel 3-alkylindole derivatives as selective and highly potent myeloperoxidase inhibitors. Soubhye J, Aldib I, Elfving B, et al. J. Med. Chem. 56(10), 3943-58, (2013)


Matrix metalloproteinase inhibition lowers mortality and brain injury in experimental pneumococcal meningitis. Liechti FD, Grandgirard D, Leppert D, et al. Infect. Immun. 82(4), 1710-8, (2014)


Turnover capacity of coprinus cinereus peroxidase for phenol and monosubstituted phenols Aitken MD and Heck PE Biotechnol. Prog. 14(3), 487-92, (1998)


Maltose-binding protein switches programmed cell death in Nicotiana glutinosa leaf cells. Gholizadeh A Tsitol. Genet. 48(2), 20-7, (2014)


[NETs in pathogenesis of vasculitis]. Nakazawa D, Nishio S, Tomaru U, et al. Nihon Jinzo Gakkai Shi 56(2), 117-23, (2014)


[Plasma levels of anti-oxidant markers during general anesthesia--a comparison between remifentanil- and epidural-based anesthesia]. Enohata K, Hasegawa-Moriyama M, Kuniyoshi T, et al. Masui. 63(3), 328-32, (2014)


[Homocysteine peroxidase activity in rat blood plasma: stoichiometry and enzymatic character of the reaction]. Razygraev AV Biomed. Khim. 59(6), 636-43, (2013)


[Inner ear 3D-FLAIR magnetic resonance image evaluation of MPO-ANCA related angitis patients]. Kato K, Sone M, Teranishi M, et al. Nippon. Jibiinkoka Gakkai Kaiho 116(11), 1192-9, (2013)


Resolvin D1 attenuates lipopolysaccharide induced acute lung injury through CXCL-12/CXCR4 pathway. Yaxin W, Shanglong Y, Huaqing S, et al. J. Surg. Res. 188(1), 213-21, (2014)


[Effect of population density on enzymatic activity of antioxidative and phenol oxidase systems of imagoes and nymphs of the marble cockroach Nauphoeta cinerea]. Murzagulov GS, Saltykova ES, Gaĭfullina LR, et al. Zh. Evol. Biokhim. Fiziol. 49(1), 24-9, (2013)


An abundant dysfunctional apolipoprotein A1 in human atheroma. Huang Y, DiDonato JA, Levison BS, et al. Nat. Med. 20(2), 193-203, (2014)


Export of functional Streptomyces coelicolor alditol oxidase to the periplasm or cell surface of Escherichia coli and its application in whole-cell biocatalysis. van Bloois E Appl. Microbiol. Biotechnol. 83(4), 679-87, (2009)


Biosynthesis of N,N-dimethyltryptamine (DMT) in a melanoma cell line and its metabolization by peroxidases. Gomes MM, Coimbra JB, Clara RO, et al. Biochem. Pharmacol. 88(3), 393-401, (2014)


Effects of native and myeloperoxidase-modified apolipoprotein a-I on reverse cholesterol transport and atherosclerosis in mice. Hewing B, Parathath S, Barrett T, et al. Arterioscler. Thromb. Vasc. Biol. 34(4), 779-89, (2014)


TRPV1 and TRPA1 antagonists prevent the transition of acute to chronic inflammation and pain in chronic pancreatitis. Schwartz ES, La JH, Scheff NN, et al. J. Neurosci. 33(13), 5603-11, (2013)


Chrysin ameliorates chemically induced colitis in the mouse through modulation of a PXR/NF-κB signaling pathway. Dou W, Zhang J, Zhang E, et al. J. Pharmacol. Exp. Ther. 345(3), 473-82, (2013)


Inhibition of NADPH oxidase prevents acute lung injury in obese rats following severe trauma. Xiang L, Lu S, Mittwede PN, et al. Am. J. Physiol. Heart Circ. Physiol. 306(5), H684-9, (2014)


Deficiency Of The E3 Ubiquitin Ligase TRIM32 In Mice Leads To A Myopathy With A Neurogenic Component. Kudryashova, E., et al. Hum. Mol. Genet. 18, 1353-67, (2009)


Polyandric acid A, a clerodane diterpenoid from the Australian medicinal plant Dodonaea polyandra, attenuates pro-inflammatory cytokine secretion in vitro and in vivo. Simpson BS, Luo X, Costabile M, et al. J. Nat. Prod. 77(1), 85-91, (2014)


Metabolic responses to high-fat diets rich in n-3 or n-6 long-chain polyunsaturated fatty acids in mice selected for either high body weight or leanness explain different health outcomes. Nuernberg K, Breier BH, Jayasinghe SN, et al. Nutr. Metab. 8(1), 56, (2011)


Rise and fall of an anti-MUC1 specific antibody. Thie H PLoS ONE 6(1), e15921, (2011)


Latent cytomegalovirus infection exacerbates experimental colitis. Onyeagocha C Am. J. Pathol. 175(5), 2034-42, (2009)


Berberine attenuates bleomycin induced pulmonary toxicity and fibrosis via suppressing NF-κB dependant TGF-β activation: a biphasic experimental study. Chitra P, Saiprasad G, Manikandan R, et al. Toxicol. Lett. 219(2), 178-93, (2013)


β2 integrin-mediated cell-cell contact transfers active myeloperoxidase from neutrophils to endothelial cells. Jerke U, Rolle S, Purfürst B, et al. J. Biol. Chem. 288(18), 12910-9, (2013)


Mammalian target of rapamycin regulates IL-10 and resistance to Pseudomonas aeruginosa corneal infection. Foldenauer ME, McClellan SA, Berger EA, et al. J. Immunol. 190(11), 5649-58, (2013)


Serum phospholipid fatty acids, genetic variation in myeloperoxidase, and prostate cancer risk in heavy smokers: a gene-nutrient interaction in the carotene and retinol efficacy trial. Cheng TY, King IB, Barnett MJ, et al. Am. J. Epidemiol. 177(10), 1106-17, (2013)


Regulation of gene expression in plants through miRNA inactivation. Ivashuta, S PLoS ONE 6(6), e21330, (2011)


Synthesis of cytochrome c oxidase subunit 1 is translationally downregulated in the absence of functional F1F0-ATP synthase. Soto IC Biochim. Biophys. Acta 1793(11), 1776-86, (2009)


Biomarkers of cardiovascular disease are increased in untreated chronic periodontitis: a case control study. Ramírez JH, Parra B, Gutierrez S, et al. Aust. Dent. J. 59(1), 29-36, (2014)


A novel benzo[d]imidazole derivate prevents the development of dextran sulfate sodium-induced murine experimental colitis via inhibition of NLRP3 inflammasome. Liu W, Guo W, Wu J, et al. Biochem. Pharmacol. 85(10), 1504-12, (2013)


A new family of receptor tyrosine kinases with a venus flytrap binding domain in insects and other invertebrates activated by aminoacids. Ahier, A PLoS ONE 4(5), e5651, (2009)


3. From Concept to Product Development Enzyme Immunoassay, (1996), 169-171

4. Zollner, H. Handbook of Enzyme Inhibitors 2nd ed., 1993, 367-368

Bergmeyer, H.U., et. al. Methods of Enzymatic Analysis, (1974), 1205-1227

Bernt, E. and Bergmeyer, H.U. Methods of Enzymatic Analysis, (1974), 2246-2248

Related Products


Product #


Add to Cart

S2002 Sodium azide, ReagentPlus®, ≥99.5%


Product #


Add to Cart

D9143 o-Dianisidine, peroxidase substrate
A0156 N-(4-Aminobutyl)-N-ethylisoluminol, ≥90%
A4685 Luminol sodium salt
A1888 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, ≥98% (HPLC)
G5502 Guaiacol, oxidation indicator
A1661 N-(6-Aminohexyl)-N-ethylisoluminol
A3537 5-Aminosalicylic acid, ≥99%
A4382 4-Aminoantipyrine, reagent grade
A8264 4-Aminophthalhydrazide
A5754 3-Amino-9-ethylcarbazole, ≥95%, powder
A8511 Luminol, ≥97% (HPLC)

Technical Service:

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Bulk Ordering & Pricing:

Need larger quantities for your development, manufacturing or research applications?