Horseradish peroxidase: an overview (2023)

Horseradish peroxidase (HRP) is an enzyme that catalyzes the oxidation of diaminobenzidine, forming a high-electron-density product that can be easily identified in osmium tetroxide-fixed tissues for electron microscopy;

Outside:From Molecules to Networks (Third Edition), 2014

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Human Research Programs (HRP)

InThe Joint Commission International Accreditation Standards Manual for Hospitals, 2020

Purpose of HRP.6

Research in humans may involve new types of surgical procedures, the use of new medications, or off-label/off-label uses (Without brand) of drugs in current formulations (of current drug formulations), ÖUse of adult treatment modalities in pediatric populations and many other research topics and methods. The integration of research activities into daily clinical practice is of fundamental importance;For example,the process of ordering, dispensing, and administering study drugs. Routine processes also include the reporting of adverse events through quality monitoring and patient safety processes. Therefore, reporting of an adverse event associated with inpatients in a research protocol should be made to the hospital's quality control mechanism, as well as to the research sponsor or CRO. (See alsoQPS.7 y QPS.7.1)

Reporting of events related to research protocols can provide important information for understanding the overall quality and safety of hospital patient care.For example,a significant adverse event when a drug is used for an off-label purpose (Without brand) is important patient safety information that should be part of the hospital's ongoing medication management process. Equally important is the handling and disposal of certain experimental investigational drugs, which should be part of hazardous materials management. Additionally, medical devices used in experimental procedures require supervision and maintenance.

Therefore, all aspects of the human research program should be evaluated against the quality and safety programs of the hospital to which they apply, and ongoing reporting and monitoring processes within the hospital should then be incorporated into the research program. This should also be the case when some investigative activities are carried out by a CRO. (See alsoGLD.6)

Protein Purification Guide, 2nd Edition

Alice Alegria-Schaffer, ... Krishna Vattem, enMethods in enzymology, 2009

5.5 Brown or yellow streaks on the membrane

HRP turns brown when oxidized and inactive. Within a given amount of conjugated enzyme, there is always a part that is oxidized. In an optimized system, the amount of HRP oxidized is minimal and cannot be visualized on the blot. The appearance of yellow or brown bands indicates the presence of a large amount of HRP and therefore the oxidized and inactive part is visible. A blotting system that results in yellow bands requires optimization using much less enzyme conjugate. Also, too much HRP in a localized area produces a large number of free radicals during enzyme activity. Free radicals can inactivate HRP and damage the antibodies, target, and membrane, preventing effective reprobing.

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Human Subject Research Programs (HRP)

InJoint Commission on Hospitals International Accreditation Standards, 2020

(Video) Horseradish Peroxidase (HRP)

Intent of HRP.7 and HRP.7.1

A hospital conducting clinical investigations, clinical investigations, or clinical trials with patients recognizes that its primary responsibility is the health and well-being of patients. The hospital educates patients and their families on how to access research relevant to patients' treatment needs.

To help patients and their families make decisions about participating in research, the hospital establishes policies and procedures for obtaining informed consent. (See alsoCCP.4.1) Through the informed consent process, patients and family members acquire knowledge of the research and the role of patients in the research so that they can decide autonomously whether to participate or not. The information provided during the consent process includes:

an explanation of the research, the duration of patient participation, and the procedures to be followed by patients;

expected benefit;

potential discomfort and risks;

alternative treatments and procedures that may also be beneficial;

the extent to which the confidentiality of records is maintained;

Compensation or medical treatment available in case of injury;

a statement that participation is voluntary;

Statement that refusing to participate or withdrawing from participation will not affect care or access to Hospital services; AND

Who to contact if you have questions about the research.

Safeguards are put in place through the hospital's research review function to protect vulnerable patients who are at risk of being coerced or improperly influenced to participate in research projects. Patients at risk include children, inmates, pregnant women, people with intellectual disabilities, those who are economically or educationally disadvantaged, and others who are limited or unable to make informed or voluntary decisions about their participation in research. Another group that can be considered a vulnerable population is hospital staff. Staff may feel pressured to participate;For example,when the principal investigator is your supervisor.

Endocytosis studies

Wendy S. Garrett, Ira Mellman, enDendritic cells (second edition), 2001


Meerrettich-Peroxidase(HRP) is a glycoprotein that is absent from most mammalian cells. It can be used in both liquid phase and receptor-mediated probe. HRP has been shown to be a ligand for MR (Stahlet al., 1978). It is a convenient tracer for immunocytochemistry;in the place, HRP can be detected by reaction with diaminobenzidine. Its concentration can be measured by a colorimetric assay.o-Phenylenediamine (OPD) and hydrogen peroxide (Strauss, 1964). Polyclonal sera directed against HRP are commercially available and are useful for fluorescence microscopy imaging. HRP has been a standard marker for the endocytic pathway for nearly four decades (stone manet al., 1974). It is relatively nontoxic and has only been shown to disrupt the endocytic pathway in thioglycolate-stimulated macrophages.Schwansonet al., 1985).

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Plasmodium species

Dr. John E. Bennett, aMandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 2020

rapid diagnostic tests

Although the evaluation of Giemsa-stained thick and thin swabs remains the accepted standard for malaria diagnosis, rapid diagnostic tests (RDTs) are becoming more useful.484490In situations where expert microscopic examination is delayed or difficult, medical decision-making and malaria case management can greatly benefit from the proper use of RDTs. In US healthcare, the CDC recommends that all positive and negative RDT results be confirmed with microscopy, which can provide additional information about species, life-cycle stages, and range of parasitemia that may be useful for clinical management. Two types of RDTs, based on different detection schemes, are currently available and are becoming more common.

The first type is based on the detection ofPlasmodiohistidinreiches Protein-2 (HRP-2).491In 556 travelers returning to France with suspected malaria, a US Food and Drug Administration (FDA)-approved commercial test based on HRP-2 had a sensitivity of 96% and a specificity of 99% forPlasmodioInfection versus microscopy.492In 32 US Marines returning from Liberia with febrile illness, this test had a sensitivity of 100% and a specificity of 100% forP sicklesInfection versus microscopy.493Although the HRP-2 tests are highly sensitive and specific for diagnosing malaria, they have certain limitations. First, HRP-2-based detection is limited toP sicklesand can in cases where theP sicklesEither strain does not express the HRP-2 antigen494–497or creates a prozone effect that interferes with the test.498.499Other antigen detection schemes are requiredP. vivax, P. ovale,YP. malariae.These are generally less sensitive than HRP-2 detection.P sickles,492.500This makes them less useful for diagnosing malaria in returning travelers who are normally infected with malaria.S. vivaxat least as often as withP sicklesSecond, HRP-2 tests have limited use in monitoring therapeutic response because tests are persistently positive up to 28 days after treatment. Third, the sensitivity of many rapid screening tests, e.g.P sicklesYS. vivaxInfections decrease with parasite densities of less than 100 to 1000/µL,500This makes them less useful for diagnosing malaria in non-immune returnees, who may show malaria symptoms when parasite density is low. A recently improved HRP-2 based RDT format may improve the detection ofP sicklesInfection up to 10 times.501.502WHO provides a list of prequalified malaria RDT products and manufacturers ( In the United States, the BinaxNOW Malaria Test (Abbott, Abbott Park, IL) is FDA-approved for use in hospitals and commercial laboratories, but not for physicians or patients (

(Video) Horse Radish Peroxidase (HRP) Mechanism of Action

Nanoshielding of enzymes with carbon nanotubes and magnetic nanoparticles

Ankarao Kalluri, ... Challa V. Kumar, enMethods in enzymology, 2020

4.9 Preparation of the bioCNT-HRP complex

4.9.1 Equipment


UV-Vis Spectrometer (Agilent Technologies, Santa Clara, CA)

4.9.2 Materials


Meerrettich-Peroxidase, HRP (Calzyme Laboratories, Inc., USA, Activity 230U/mg, Carga 65-3-100)


Sodium phosphate puffer 10 mM, pH 7.2


1.5 mL volume Eppendorf tubes (Dot Scientific Inc.)

4.9.3 Procedure


Prepare stock solutions of HRP (~5 mg/mL) in 10 mM phosphate buffer at pH 7 and determine the molar concentration (Soret absorbance at 403 nm) using absorbance spectroscopy.


Prepare a series of dispersions of the bioCNT-HRP complex by increasing HRP enzyme concentrations from 0.5 to 1.0 mg/mL with the solid dispersion of bioCNT (1 mg/mL).


The dispersed bioCNT-HRP complex was prepared by mixing 300 μl of HRP stock solution (5 mg/ml, pH 7) and 500 μl (2 mg/ml) of diluted bioCNT dispersion with 200 μl of phosphate buffer in a tube. 2ml Eppendorf. This complex mixture was mixed well and incubated for one day.


The final sample was centrifuged at 13.3 KRPM for 2 h to separate the pellet from the bioCNT-HRP complex and unbound HRP (supernatant) was quantified using the Soret absorbance at 403 nm, this value was used more, around the HRP. immobilized (bound) on the bioCNT-HRP complex. After the incubation and centrifugation steps, store the samples at 2-8 °C.


The HRP enzyme immobilized in the bioCNT-HRP complex represents approximately 20-30% (w/w) compared to the initial free HRP enzyme (1 mg/ml).

Tip 1:A shake table can be used to mix the solution and reduce enzyme loading time.

Tip 2:Both CNT and proteins absorb at a wavelength of 280 nm, so estimating the protein concentration at 280 nm introduces large errors. Therefore, we used the Soret absorbance at 403 nm to measure the absorbance of HRP in the bioCNT-HRP complex, which is more reliable and accurate compared to the absorbance at 280 nm.

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Enzymatic nanoarchitectures: Enzymes shielded with graphene

Sheela Berchmans, ... Palaniappan Arumugam, enMethods in enzymology, 2018

7 Post-functionalization of GCE/Ct-RGO-PAMAM by the enzyme horseradish peroxidase

7.1 Equipment

Microcentrifuge tubes, micropipettes and tips, coolers and racks for microcentrifuge tubes.

7.2 Materials

Meerrettich-Peroxidase(HRP, Type I, essentially salt-free, lyophilized powder, 50-150U per mg solid), glutaraldehyde (GA, 25% aqueous solution) and PBS pH 7 buffer.

(Video) Horseradish Peroxidase | HRP Enzyme |

7.3 Preparation of phosphate buffer (PBS, pH 7)


Die 0.1METROPhosphate buffer is made with KH2AFTER4and NaOH.


The 6.8 g of carbohydrates2AFTER4is placed in a standard volumetric flask and dissolved with 100 mL of water and 1.2 g of NaOH is dissolved with 100 mL of water.


The prepared NaOH solution is added to the KH2AFTER4solution and make up the volume to 500 ml.

7.4 Immobilization of enzymes


GCE/Ct-RGO-PAMAM and GCE-PAMAM are activated with 1% aqueous glutaraldehyde solution for 3 h.


The activated electrodes are washed with water and incubated in PBS (pH 7) containing HRP (5 mg/ml).−1) a 4°C durante 12h.


After 12 h, the electrodes are removed from the HRP solution and washed repeatedly with PBS to remove physically adsorbed HRP.


The HRP-modified working electrode thus prepared is stored at 4°C when not in use.

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Biosensors based on direct electron transfer from proteins

Shengshui Hu, ... Yanxia Xu, enElectrochemical sensors, biosensors and their biomedical applications, 2008 Direct transfer of electrons from HRP

Meerrettich-Peroxidase(HRP) is a member of the large class of peroxidases, which are enzymes defined as oxidoreductases that use hydroperoxide as an electron acceptor. Due to its commercial availability in high purity, HRP has long been a representative system to study the structure, dynamic and thermodynamic properties of peroxidases, particularly to understand their biological behavior in catalyzing the oxidation of substrates by H2o2[125]. HRP can react with H2o2to form a strong enzymatic oxidant known as compound I, a two equivalent oxidized form containing a heme oxyferryl (Fe4+=O) and a cationic radical φ of porphyrin. Compound I is catalytically active and can withdraw an electron from the substrate to form a second intermediate called compound II, which is subsequently reduced to the resting state of the native HRP-Fe(III) enzyme by accepting an additional electron from the substrate. HRP-Fe(III) can also be further reduced to HRP-Fe(II). Efficient electron transfer between HRP and electrodes has been reported for many years.126]. In most cases, however, it has been shown that direct electrochemistry in the presence of H2o2or other peroxides determined by amperometry and attributed to the electrochemical reduction of compound I or compound II. Few examples of HRP-independent quasi-reversible CVs in the absence of peroxides have been reported, probably due to the large molecular mass and extended structure of HRP and the inaccessibility of its redox centers.127–130]. ferri [127128] reported a pair of nearly reversible CV peaks for the HRP Fe(III)/Fe(II) redox couple when trapping HRP on tributylmethylphosphonium chloride (TBMPC) polymer film attached to PG electrodes on anion exchange resin. Chen [129130] then studied the direct electrochemistry of the HRP Fe(III)/Fe(II) pair by CV on DDAB and DNA films on PG electrodes. These films provided a suitable microenvironment for the HRP, which greatly facilitated the exchange of electrons between the HRP and the electrodes. Electrochemical catalytic reduction of H2o2by HRP in these films has also been described. Recently, a new functional cysteine ​​membrane was constructed from Nafion [131]. Fast and direct electron transfer from HRP was performed on the membrane-functional modified gold electrode with good stability and repeatability.Poly(ester sulfonic acid) under the tradename Eastman AQ is a type of anionic ionomer. Unlike another more popular ionomer, Nafion, this thermoplastic amorphous polymer produces low-viscosity, translucent dispersions in water without the addition of organic solvents. AQ films cast on electrodes do not dissolve in water. Like Nafion, AQ films preferentially bind hydrophobic cations and exclude negatively charged species [132]. Enzymes can be added directly to aqueous dispersions of AQ ionomers and deposited on solid surfaces to form films without denaturation or significant loss of activity [133]. Direct electrochemistry of small redox proteins such as cytC[134], MB [135] y Hb [136] in AQ films on PG electrodes has been previously studied. So Huang Rong and Hu Naifei [137] prepared stable ionomeric poly(sulfonic acid ester) or Eastman AQ29 films on PG electrodes and achieved direct electrochemistry for the incorporated HRP enzyme. Cyclic voltammetry of HRP-AQ films revealed a pair of well-defined and nearly reversible peaks around -0.33 V (versus SCE) at pH 7.0 in blank buffers, characteristic of HRP-heme redox. Fe(III)/Fe(II). couple. Electron transfer between the HRP and PG electrodes was greatly facilitated in the AQ films. Reflectance-infrared absorption (RAIR) and UV-visible (UV-Vis) absorption spectra showed that HRP retained a nearly native conformation in AQ films. HRP embedded in AQ films retained electrocatalytic activity for oxygen, nitrite, and H2o2.

Agarose is a polysaccharide with an average molecular weight of 120,000 Da, composed of 1,3-l-dgalactopyranose and 3,6-anhydro-k-l-galactose units linked in 1,4[138]. In a hot solution, the agarose chains exist in a rigid, disordered configuration. Upon cooling below 40 °C, the whorls form ordered whorls, which subsequently accumulate into thick bundles in which there are large water pores. The agarose gel matrix exhibits strong elasticity, high turbidity, aqueous microenvironment, and bioaffinity, making it an ideal biopolymer for immobilizing proteins on solid substrates. Agarose gel has been found to be the best for constructing the cytochrome P450 bioreactor compared to other gels such as PAM, calcium alginate, and pre-polymerized polyacrylamide hydrazide [139]. Liu [140] immobilized HRP on agarose hydrogel-modified edge-plane PG electrodes and obtained direct electrochemistry of HRP. The protein encapsulated in the agarose film underwent rapid direct electron transfer reactions accordingly.


Hemi0' was linearly dependent on the pH of the solution (redox-Bohr effect), indicating that the electron transfer was proton-coupled. UV-Vis absorption spectra and RAIR spectra indicated that the conformation of HRP in the agarose film differed little from that protein alone and that the conformation changed reversibly in the pH range 3.0-10.0. Atomic force microscopy images of the agarose film revealed a stable, crystal-like structure, possibly formed due to the synergistic interaction of hydrogen bonds between DMF, agarose hydrogel, and HRP. This suggested a strong interaction between the heme protein and the agarose hydrogel. DMF played an important role in immobilizing proteins and increasing the rate of electron transfer between the protein and the electrode.

It is known that the TiO2It is widely used in cosmetics, solar cells, batteries, additives in toothpaste and white paint and others. Recently, there has been considerable interest in the use of TiO2Nanoparticles as a film-forming material due to its highsurface, optical transparency, good biocompatibility and relatively good conductivity. Various TiO2The films have also been used to immobilize proteins or enzymes on the electrode surface for mechanistic studies of proteins or to fabricate electrochemical biosensors. For example, Durrant and his colleagues immobilized a variety of proteins on nanoporous TiO2.2developed film-modified electrodes and successfully used this strategy to develop electrochemical and optical biosensors.141142]. Luo and his collaborators used nanocrystalline TiO22Films on electrodes to trap heme proteins such as cytC, Mb and Hb and looked at the direct electrochemistry of these proteins [143]. Cyt accumulation and electroactivityCin TiO layer-by-layer mesoporous films2and phytate in ITO electrodes has also been studied [144]. Titanium oxide sol-gel matrix films were used to immobilize HRP and, with the help of mediators, HRP-TiO2Film electrodes were used to detect H2o2by amperometry [66,145]. House group [146] also incorporated HRP into TiO2Modified nanoparticle films on electrodes to achieve direct electron transfer from HRP. HRPTiO2Film electrodes were prepared by pouring the mixture of HRP solution and aqueous dispersion of titanium oxide nanoparticles onto PG electrodes and evaporating the solvent. The HRP embedded in TiO2The movies showed a pair of well-defined and nearly reversible CV peaks at around -0.35 V in pH 7.0 buffer, reflecting that the rate of electron exchange between the enzyme and the PG electrodes was increased. considerably in TiO2Nanoparticle film microenvironment. TiO HRP2The film electrodes were quite stable and suitable for long-term voltammetry experiments. UV-Vis spectroscopy showed that the position and shape of the Soret absorption band of HRP in TiO2The films were almost unchanged and differed from those of hemin or hemin-TiO2films, suggesting that HRP retains its native-like tertiary structure in TiO2films. The electrocatalytic activity of HRP embedded in TiO2Movies about O2yh2o2It has remained.

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(Video) Horseradish peroxidase

In vitro and in vivo models of BBBs to assess brain-targeted drug delivery

Bhupesh Sharma, GT KulkarniBrain-directed drug delivery system, 2019

4.1.5 Meerrettichperoxidasa (HRP)

HRP was introduced for the analysis of electron microscopic structures (Strauss, 1959), because it is possible to make the reaction product an electron-dense material (Brightman y Reese, 1969), allowing microscopic examination of the BBB structure as the HRP antibody binds to endothelial cell walls and tight junctions (Brightman y Reese, 1969). In an in vivo study, HRP is typically injected, and in an in vitro system, it is typically introduced into the donor chamber. Once introduced into the in vitro system, the cells are dissected and can be used for visualization using electron microscopy. The evaluation is purely visual or based on image analysis software. The main advantage of HRP is that it requires an extremely small amount of antibodies and is highly specific for a given cell type.

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Enzyme modification and conjugation

Greg T. Hermanson, aBioconjugate Techniques (3rd Edition), 2013

1.1 Meerrettichperoxidasa (HRP)

HRP (donor: hydrogen peroxide oxidoreductase; EC, derived from horseradish roots, is an enzyme with a molecular weight of 40,000 that can catalyze the reaction of hydrogen peroxide with certain electron-donating organic substrates to produce brightly colored productsFigure 22.1). The reaction of HRP with its basic substrate, H2o2, forms a stable intermediate that can dissociate in the presence of a suitable electron donor, thus oxidizing the donor and possibly producing a color change. The donor may consist of oxidizable molecules such as ascorbate, cytochromeC, ferrocyanide or leuco forms of many dyes. A wide range ofElectron donating dye substrates are commercially available for use as HRP detection reagents. Some of them can be used to form soluble colored products for use in spectrophotometric detection systems, while other substrates form insoluble products especially suitable for staining techniques. In addition, substrates are available that generate fluorescent or chemiluminescent products upon HRP oxidation. Chemiluminescent substrates are among the most sensitive of all detection reagents, making it easy to detect amounts as low as attograms of many target analytes. The optimum pH for HRP is 7.0, although certain substrate detection reactions can be performed at slightly different than neutral pH values.

Horseradish peroxidase: an overview (1)

Figure 22.1. Horseradish peroxidase is shown as a ribbon structure with the heme ring at its active site and two bound calcium ions. The molecular model is based on the 1H58 structure in the RCSB protein database.Berglundet al.(2002).

The use of antibody-HRP or streptavidin-HRP conjugates in peroxidase-catalyzed enhanced chemiluminescence assays may result in one of the most sensitive detection methods for target analyte determination in ELISA and Western blot applications. The cascade of reactions that occurs during HRP catalysis can be drastically enhanced by the addition of various enhancer molecules that generate oxidized intermediates that lead to the oxidation and light emission of a chemiluminescent substrate such as luminol.Vdovenkoet al.(2012)analyzed this response using a multifactorial design of experiments (DOE) approach to find the best combination and concentration of H2o2, luminol, and two different enhancer compounds (3-(10′-phenothiazinyl)propane-1-sulfonate and 4-morpholinopyridine. This combination resulted in the best signal-to-noise ratio and longest chemiluminescence emission at optimized concentration.

HRP is a hemoprotein that contains Photohemin IX as its prosthetic group. The presence of the heme structure gives the enzyme its characteristic color and its absorbance maximum at 403 nm. The ratio of its absorbance in solution at 403 nm to its absorbance at 275 nm, called the RZ or purity number ratio, can be used to determine the purity of the to approach the enzyme. However, there are at least seven isoenzymes for HRP (Shannonet al., 1966;kayet al., 1967;Stricklandet al., 1968) and their RZ values ​​vary from 2.50 to 4.19. Therefore, unless the RZ ratio is precisely known, or precisely known for the particular HRP isoenzyme used in the preparation of an antibody-enzyme conjugate, subsequent measurement after crosslinking would give questionable results for determining the levels present in the existing HRP delivering conjugate. amount.

HRP is a glycoprotein that contains significant amounts of carbohydrates. Its polysaccharide chains are often used in cross-linking reactions to couple the enzyme to target molecules. Mild oxidation of glycan sugar residues associated with sodium periodate generates reactive aldehyde groups that can be used for conjugation with amine-containing molecules. The reductive amination of oxidized HRP on antibody molecules in the presence of sodium cyanoborohydride is perhaps the simplest method for preparing highly active conjugates with this enzyme.Chapter 4, Section 1.4, YChapter 20, Section 1.3).

Other methods of HRP conjugation include the use of the homobifunctional reagent glutaraldehyde (Chapter 5, Section 6.2, YChapter 15, Section 2.1) and the heterobifunctional crosslinker SMCC (succinimidyl-4-(norte-maleimidometil)ciclohexan-1-carboxilato) (Chapter 6, Section 1.3). A two-step protocol using glutaraldehyde is commonly used to try to limit the extent of oligomer formation. However, even using the most controlled reactions, this method often causes unacceptable amounts of conjugate to precipitate. Despite this drawback, glutaraldehyde conjugation is still used routinely, particularly in the preparation of some antibody reagents and enzymes that feed established diagnostic assays. the use of thenorte- The hydroxysuccinimide ester (NHS) maleimide crosslinker, SMCC, offers much better control over the conjugation process. Generally, SMCC is first reacted with HRP to produce a derivative containing sulfhydryl-reactive maleimide groups. HRP activation of the native enzyme should result in the modification of a maximum of about two amine groups in the protein since HRP contains only two lysines. An increase in the level of activation can be achieved if the enzyme is first modified with ethylenediamine (EDA) using carbodiimide-EDC according to the methods described in US Pat.chapter 19for the production of cationized bovine serum albumin (cBSA). EDA-modified HRP is also more stable than the unmodified version, so cationization may have advantages in retention of enzyme activity. The maleimide-activated enzyme can be purified and lyophilized, providing a ready source of HRP modified to react with a sulfhydryl-containing antibody. Various preactivated forms of this enzyme are available from Thermo Fisher.

The size of the HRP is an advantage in the production of antibody-enzyme conjugates since the total size of the complex can also be made small. Relatively small molecular weight conjugates can penetrate cell structures better than large polymeric complexes. For this reason, HRP conjugates are often the best choice for immunohistochemical (IHC) and immunocytochemical staining techniques. The small size of the conjugate means better accessibility to antigenic structures within tissue sections.

Another key benefit of HRP is its strength and stability, especially under the conditions used for crosslinking. HRP is stable for years in the lyophilized state and the purified enzyme can be stored in solution at 4°C for many months without significant loss of activity. The enzyme also retains excellent activity after being modified with a conjugating reagent or oxidized to periodate.they form aldehyde groups on their polysaccharide chains. Depending on the methods used for cross-linking, HRP conjugates can be designed to have either a high enzyme/antibody ratio or a low ratio, both of which retain high specific activity.

The disadvantages associated with HRP are multiple. The enzyme contains only two available primary ε-amine groups (extraordinarily few for most proteins), limiting its ability to be activated by amine-reactive heterobifunctionals. HRP is sensitive to the presence of many antibacterial agents, particularly azide. It is also reversibly inhibited by cyanide and sulfide (Theorell, 1951). Finally, although the enzymatic activity of HRP is extremely high, its shelf life or practical substrate development time is somewhat limited. After about an hour of substrate renewal, its activity can drop drastically in some situations.

However, HRP is by far the most popular enzyme used in antibody-enzyme conjugates. A study on the use of enzymes revealed that HRP is incorporated into approximately 80% of all antibody conjugates, most of which are used in diagnostic test systems.

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(Video) 06 - Enzyme Kinetics of Horseradish Peroxidase



What does horseradish peroxidase enzyme do? ›

Horseradish peroxidase (HRP) has the ability to catalyze the transfer of two electrons from a substrate to hydrogen peroxide to generate water and an oxidized substrate. HRP is frequently used in conjugates to detect the presence of a protein target.

What is the mechanism of action of horseradish peroxidase? ›

Horseradish peroxidase (HRP) catalyzes the polymerization of free heme (β-hematin formation) through its oxidation. Heme when added to HRP compound II (Fe IV=O) causes spectral shift from 417 nm (Compound II) to 402 nm (native, Fe III) indicating that heme may be oxidized via one-electron transfer.

What is horseradish peroxidase antibody? ›

Horseradish peroxidase (HRP) is a rapid and stable enzyme commonly used as a detection reagent in immunoassays such as western blot, immunohistochemistry and ELISA. We offer high quality HRP secondaries that includes antibodies against diverse species and their isotypes as well as fragment and pre-adsorbed forms.

What is the specific activity of horseradish peroxidase? ›

The pH optimum of HRP is in the range of 6.0 to 6.5. Activity at pH 7.5 is 84% of the maximum. The enzyme is most stable in the pH range of 5.0 to 9.0.

What does horseradish do to your body? ›

Horseradish root is naturally rich in antioxidants, which can help protect your body from cellular damage by attaching themselves to free radicals. Early studies also suggest that horseradish may prevent the growth of colon, lung, and stomach cancer cells, though more research in humans needs to be done.

How does horseradish affect the body? ›

Supports Immunity. In addition, the nutrients in horseradish have strong antioxidant properties, which promote a healthy immune system. Along with the high vitamin C content in horseradish, its antioxidants help produce and stimulate white blood cell activity, which are crucial to a strong immune system.

What is the physiological purpose of peroxidase? ›

Peroxidase is an enzyme found in a wide variety of organisms, from plants to humans to bacteria. Its function is to break down hydrogen peroxide (H2O2), which is one of the toxins produced as a byproduct of using oxygen for respiration.

How does HRP bind to antibody? ›

Horseradish peroxidase is coupled to IgG antibody in a two-step procedure. In the first step monosaccharide residues in the enzyme are oxidized with periodate to produce aldehyde groups. Then, in the second step, the aldehyde groups are allowed to react with amino groups in the IgG antibody.

How is HRP detected? ›

It is a convenient tracer for immunocytochemistry; in situ, HRP can be detected by reaction with diamino-benzidine. Its concentration can be measured by colorimetric assay using O-phenylenediamine (OPD) and hydrogen peroxide (Straus, 1964).

What foods are high in peroxidase? ›

The peroxidase enzyme activities of some fresh vegetables (cabbage, leeks, carrot, spinach, celery, squash, potatoes, onions and green beans) were determined. The peroxidase activities of cabbage and green beans were high. Onions showed very little peroxidase activity.

Is peroxidase harmful to humans? ›

Unfavorable excessive peroxidase activity is implicated in oxidative damage of cells and tissues, thereby initiating the variety of human diseases.

Where does horseradish peroxidase come from? ›

The enzyme horseradish peroxidase (HRP), found in the roots of horseradish, is used extensively in biochemistry applications. It is a metalloenzyme with many isoforms, of which the most studied type is C. It catalyzes the oxidation of various organic substrates by hydrogen peroxide.

Why is it important for humans to have peroxidases in their cells? ›

Peroxidases play a significant role in antioxidant defense system of living organisms and are actively involved in oxyradical oxidation, hormone biosynthesis, and innate immunity.

What are the health benefits of horseradish peroxidase? ›

It's also rich in antioxidants and a variety of enzymes, including horseradish peroxidase. Because of the presence of these compounds, it may prevent bacterial growth, fight off illness and disease with antioxidants, and provide a healthy mix of vitamins and minerals to help supplement a balanced diet.

Does horseradish detoxify the liver? ›

Horseradish contains compounds called glucosinolates, which promote healthy cell growth and increase the liver's ability to detoxify carcinogens.

Is horseradish good for your gut? ›

Digestive Problems

Though horseradish can help treat certain digestive issues, there is evidence that it can also aggravate intestinal ulcers, inflammatory bowel disease, or other digestive conditions that might be present that might be present especially if there is mucosal i. damage.

Why does horseradish go to your brain? ›

The horseradish's primary chemical irritant, allyl isothiocyanate, stimulates the same class of chemical receptors on the same sensory cells in your mouth, throat, nose, sinuses, face and eyes as do tear gas agents and pepper spray's capsaicin, the chemical in chili peppers that lights your mouth on fire.

Is horseradish inflammatory? ›

Horseradish root is also known for its anti-inflammatory and antibacterial characteristics and is consequently used for the treatment of acute sinusitis, bronchitis, and urinary bladder infection [2–5].

Does horseradish affect blood pressure? ›

Potassium present in horseradish helps to take care of your heart by lowering blood pressure and regulating the flow of fluids and nutrients.

Where is peroxidase found in the body? ›

Abstract. Human whole saliva contains two peroxidases, salivary peroxidase (hSPO) and myeloperoxidase (hMPO), which are part of the innate host defence in oral cavity.

What bacteria produces peroxidase? ›

Peroxidases produced from microbial sources such as bacteria (Bacillus sphaericus, Bacillus subtilis, Pseudomonas sp., Citrobacter sp.), Cyanobacteria (Anabaena sp.), fungi (Candida krusei, Coprinopsis cinerea, Phanerochaete chrysosporium), actinomycetes (Streptomyces sp., Thermobifida fusca), and yeast are used in ...

What does peroxidase positive mean? ›

Background: The presence of leukocytes, detected by peroxidase test in semen, can be a good indicator of infections in the male genital tract. Peroxidase positive cells have been positively correlated with elevated values of elastase, one of the major proteases liberated by granulocytes at the inflammation place.

How do you develop HRP? ›

There are four key steps to the HRP process. They include analyzing present labor supply, forecasting labor demand, balancing projected labor demand with supply, and supporting organizational goals. HRP is an important investment for any business as it allows companies to remain both productive and profitable.

What is the role of horseradish peroxidase in ELISA? ›

Posted April 24, 2020. HRP, or horseradish peroxidase, is commonly used in ELISA (enzyme-linked immunosorbent assay) since it can easily be conjugated to IgG and other proteins. In ELISA, TMB plays the role of a chromogenic substrate, and is also one of the most sensitive substrates for HRP.

Is HRP an antigen? ›

Abstract. Antibodies conjugated with horseradish peroxidase (HRP) are one of the most widely used bioreagents in the biological sciences.

What factors can affect HRP? ›

External Factors Affecting HRP
  • Competitive Conditions. HR managers seek to maintain low costs, one of the most common factors affecting human resource planning. ...
  • Regulatory Shifts. Whether it's ensuring safety or labor laws, regulatory shifts impact HR practice. ...
  • Advancing Technology.
Dec 1, 2021

How can I make my HRP more effective? ›

How to build an effective human resource planning checklist
  1. Human resource planning comprises of four comprehensive steps.
  2. STEP 1: Analyse company objectives and HR needs.
  3. STEP 2: Determine recruiting strategy and evaluate current human resources.
  4. STEP 3: Predict need.
  5. STEP 4: Planning training and development.
Jun 18, 2020

What are the 5 steps in HRP? ›

Five Planning Steps Every Organization Should Use
  • Analysis of Organizational Plans and Objectives. ...
  • Preparing a Human Resources Inventory. ...
  • Assessing Future Supply and Demand. ...
  • Matching Supply and Demand. ...
  • Establishing an Action Plan.
Jul 29, 2020

What foods have horseradish peroxidase? ›

Peroxidase is found widely distributed in higher plants (horseradish, turnip, fig sap, tobacco, potato) and microorganisms (yeast cytochrome c).

What vegetable has the most peroxidase? ›

Total protein concentration was measured by dye binding (Bradford, 1976). Among all the fresh produce assayed, ki- wifruit had the highest ascorbic acid concen- tration (Table 1). Kiwifruit and potatoes had the lowest peroxidase activity, while green beans had the highest (Fig. 1).

What causes peroxidase? ›

The activation of hydrogen peroxide by heme peroxidase generates intermediate species, with high valence, capable of abstracting electrons from different substrates. Peroxidase can be produced by bacteria135 and fungi.

Is peroxidase present in blood? ›

As a hemoprotein, hemoglobin (Hb) can, in the presence of H(2)O(2), act as a peroxidase. In red blood cells, this activity is regulated by the reducing environment.

Is hydrogen peroxide carcinogenic? ›

How likely is hydrogen peroxide to cause cancer? The International Agency for Research on Cancer (IARC) has determined that hydrogen peroxide is not classifiable as to its carcinogenicity to humans.

What organisms contain peroxidase? ›

Crystal structure of the human myeloperoxidase-thiocyanate complex. Peroxidases are found in bacteria, fungi, plants and animals.

Is horseradish peroxidase toxic? ›

May be harmful by inhalation, ingestion, or skin absorption. May cause allergy or asthma symptoms or breathing difficulties if inhaled. May cause eye, skin, or respiratory system irritation.

What is horseradish peroxidase made of? ›

1.1 Horseradish Peroxidase (HRP) HRP (donor:hydrogen peroxide oxidoreductase; EC 1.11. 1.7), derived from horseradish roots, is a enzyme of molecular weight 40,000 that can catalyze the reaction of hydrogen peroxide with certain organic, electron-donating substrates to yield highly colored products (Figure 22.1).

What metal is in horseradish peroxidase? ›

Horseradish peroxidase C has two metal centers, one of iron heme group and two calcium atoms.

What is the activity of peroxidase? ›

Peroxidases are the ubiquitous enzyme and reported to be present in all living genera. They catalyses reduction of peroxide and generate reactive oxygen species. In the present study we demonstrated that insect infestation induces peroxidase activity in sap and total soluble protein (TSP) of plant leaves.

What disease is associated with a lack of superoxide dismutase? ›

In mice, the extracellular superoxide dismutase (SOD3, ecSOD) contributes to the development of hypertension. Diminished SOD3 activity has been linked to lung diseases such as Acute Respiratory Distress Syndrome (ARDS) or Chronic obstructive pulmonary disease (COPD).

What is peroxidase enzyme used for? ›

Peroxidase enzymes have versatile applications in bioenergy, bioremediation, dye decolorization, humic acid degradation, paper and pulp, and textile industries.

What does horseradish peroxidase do in Western blot? ›

Horseradish peroxidase (HRP) catalyzes the oxidation of substrates by hydrogen peroxide, resulting in a colored or fluorescent product and the release of light as a by-product of the reaction.

What is the function of peroxidase in root vegetables? ›

Peroxidase enzymes are widely distributed in plants and animals, including bacteria, to protect cells against the effects of oxidative stress and cell damage due to hydrogen peroxide.

What foods contain peroxidase? ›

Foods containing peroxidase such as radishes, turnips, cabbage, cauliflower, horseradish, uncooked broccoli, cucumbers, mushrooms, green beans, artichokes and melons can generate falsely positive color reactions. Some kit manufacturers include alcohol in the developer to denature plant peroxidases.

Why HRP is used in western blot? ›

The use of HRP secondary antibodies and AP secondary antibodies is therefore ideal for western blot since there use allows amplification of the signal and easier detection of protein of interest in the middle of a complex protein mixture.

What does horseradish peroxidase do to ABTS Why do we need this to happen? ›

The enzyme horseradish peroxidase (HRP), found in the roots of horseradish, is used extensively in biochemistry applications primarily for its ability to amplify a weak signal and increase detectability of a target molecule.


1. Horseradish peroxidase electrostatics
(Christopher Roberts)
2. Structure of Horseradish Peroxidase
3. Horseradish Peroxidase
(3D proteins)
4. World Horseradish Peroxidase Market (HRP) - Posters Five Forces Analysis and Overview
(uttam sharma)
5. HRP secondary antibodies for western blotting
(Thermo Fisher Scientific)
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