Oxidase/Peroxidase Assays

Oxidases and peroxidases play a major role in the generation of reactive oxygen species during oxidative stress and many of them have been related to the progression of distinct diseases and even environmental toxicity.

Oxidases catalyze an oxidation-reduction reaction, especially the oxidation of a substrate by molecular oxygen (O2) as the electron acceptor  In reactions involving donation of a hydrogen atom, oxygen is reduced to water (H2O) or, in most cases, to hydrogen peroxide (H2O2).

Peroxidases are a large family of enzymes that typically catalyze a reaction of the form: ROOR' + electron donor (2 e-) + 2H+ → ROH + R'OH. For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides. Peroxidases can contain a heme cofactor in their active sites, or alternately redox-active cysteine or selenocysteine residues.

Monoamine Oxidases

Monoamine oxidases (MAO, EC are a family of enzymes which are found in the outer mitochondrial membrane and can oxidize a wide variety of endogenous primary amines. Two isoforms, MAO-A and MAO-B, have been identified based on their substrate affinity, inhibitor specificity and tissue localization. MAO-A and MAO-B are mitochondrial-bound enzymes that are ubiquitously expressed throughout the brain and other tissues (e.g. liver, placenta). Imbalance of MAO levels has been associated with schizophrenia, depression, attention deficit and other disorders. MAO-A has been implicated in panic, anxiety and depression, whereas MAO-B defects result in Alzheimer’s and Parkinson’s diseases.
Several MAO-A and MAO-B specific inhibitors such as clorgyline, brofaromine, toloxatone, and tetrindole, or selegiline and rasagiline have been used as antidepressants, but the benefits were rather modest and their usage has been limited due to side effects.

Monoamine Oxidases are also, besides the CYP450 enzymes,  the most important Phase I biotransformation enzymes. Thus, MAO assays are a common tool in drug development.  

PromoKine's Monoamine Oxidase Activity Assay Kit provides a sensitive assay to detect total monoamine oxidase activity as well as MAO-A and MAO-B isoenzyme activities separately in the presence of the specific inhibitors for MAO-A and MAO-B, clorgyline and selegiline. The assay is based on the fluorometric detection of H2O2, one of the byproducts generated during the oxidative deamination of the MAO Substrate and can detect as little as 5 µU of MAO enzymatic activity.

PromoKine’s MAO-A and MAO-B Inhibitor Screening Kits offer a rapid, simple, sensitive, and reliable test suitable for high-throughput screening of MAO-A or MAO-B inhibitors. The assays ares based on the fluorometric detection of H2O2, one of the byproducts generated during the oxidative deamination of MAO substrate. 

Myeloperoxidase (MPO) Activity Assay & Screening Kits

Myeloperoxidase (MPO) is a heme-based lysosomal enzyme most abundantly expressed in neutrophil granulocytes and stored in the azurophilic granules of the neutrophil. MPO catalyzes the production of hypochlorous acid (HClO) from hydrogen peroxide (H₂O₂) and chloride anion (Cl-, or the equivalent from a non-chlorine halide). It also oxidizes tyrosine to a tyrosyl radical using hydrogen peroxide as an oxidizing agent.
MPO is implicated in many disorders, and elevated MPO levels have been linked to coronary artery disease.

PromoKine's Myeloperoxidase (MPO) Assay Kits provide rapid, simple, highly sensitive and reliable tests suitable for high throughput activity assays of MPO.
In PromoKine’s Myeloperoxidase (MPO) Activity Assay Kit I, the HClO produced from H₂O₂ and Cl- reacts with taurine to generate taurine chloramine, which subsequently reacts with the TNB2- probe. The Positive Controls and samples will show decreased color proportional to the amount of enzyme present.
In our Myeloperoxidase (MPO) Activity Assay Kit II, MPO catalyzes the production of NaClO from H₂O₂ and NaCl. Subsequently, NaClO will react stoichiometrically with aminophenyl fluorescein (APF) to generate fluorescein, which has a strong fluorescence and can be detected at Ex/Em = 485/525 nm and is directly proportional to the MPO enzymatic activity.

PromoKine’s Myeloperoxidase (MPO) Peroxidation Activity Assay Kit provides a sensitive, quick and easy method for detecting MPO activity. In this Assay, MPO oxidizes a substrate to generate fluorescence (Ex/Em = 535/587 nm), which is directly proportional to total peroxidase activity in the sample. A specific MPO inhibitor is provided, which suppresses peroxidase activity due to MPO. This permits differentiation of MPO-mediated peroxidation from the activity of other peroxidases which may be present in the samples.

Our Myeloperoxidase (MPO) Inhibitor Screening Kit provides a fast, easy and high-throughput adaptable method for determining both MPO chlorination and peroxidation activities as well as a sensitive, quick, and easy assay for screening potential inhibitors of MPO, and identifying whether one or both activities are inhibited. The fluorescence generated is directly proportional to any peroxidase activity present. The kit also includes  an MPO Inhibitor Control to compare the efficacy of test inhibitors.

Xanthine Oxidase Activity Assay Kit

Xanthine oxidase (XO) is present in appreciable amounts in the liver and jejunum in healthy individuals and Plays a role in oxidative stress as well as several diseases such as various liver disorders. Therefore, determination of serum XO level serves as a sensitive indicator of acute liver damage such as jaundice.

PromoKine's Xanthine Oxidase Activity Assay Kit provides a fast, easy and accurate method to determine XO in a variety of samples. In the assay, XO oxidizes xanthine to hydrogen peroxide (H₂O₂) which reacts stoichiometrically with OxiRed Probe to generate a colorimetric (at λ = 570 nm) and a fluorometric (at Ex/Em = 535/587 nm) Signal whose intensity is proportional to the XO Content.

Glucose Oxidase Activity Assay Kit

The glucose oxidase enzyme (GOx) is an oxido-reductase that catalyzes the oxidation of glucose to hydrogen peroxide and D-glucono-δ-lactone. In cells, it aids in breaking the sugar down into its metabolites. GOx is involved in oxidative stress-induced cell damage and cell senescence playing a role in various disease pattern.

PromoKine’s Glucose Oxidase Assay Kit provides a convenient tool for very sensitive and convenient detection of glucose oxidase in a variety of samples. With D-glucose as a specific substrate, the absorbance  (λ = 570 nm) or fluorescence (Ex/Em = 535/585 nm) signal  is proportional to the activity of GOx in the sample.

Lysyl Oxidase Activity Assay Kit

Lysyl oxidase (LOX) is a cell-secreted amine oxidase that participates in the assembly/cross-linking of collagen and elastin fibres, producing H2O2 as a by-product. As a result, lysyl oxidase is required for the biosynthesis of functional extracellular matrices and inhibition of lysyl oxidase can result in osteolathyrism, a condition characterized by fragile connective tissue and paralysis. Recent work has also suggested that lysyl oxidase plays an important role in cancer development, promoting tumor growth and progression in vivo, cancer cell invasion, and premetastatic niche formation. Lysyl oxidase also induces vascular oxidative stress and contributes to arterial stiffness and abnormal elastin structure in hypertension.

PromoKine’s Lysyl Oxidase Activity Assay Kit allows for sensitive and quantitative evaluation of lysyl oxidase activity of purified enzyme and its inhibitors as well as secreted endogenous enzyme in cell media. Enzyme activity is detected upon oxidation of a substrate, which results in release of reaction intermediates that are subsequently detected by a LOX Probe, resulting in a fluorescent signal that can be measured at Ex/Em= 535/587 nm. Each kit includes a positive control as well as a specific lysyl oxidase inhibitor that allows the user to correct each sample for any non-specific signal.

Peroxidase Assay Kits

PromoKine’s Peroxidase Activity Assay Kit provides a convenient colorimetric and fluorometric means to measure the peroxidase activity in biological samples. In the presence of peroxidase, the OxiRed Probe reacts with H2O2 in a 1:1 stoichiometry to produce the red-fluorescent oxidation product resorufin which is quantified by colorimetric (λmax = 570nm) or fluorometric methods (Ex/Em = 535/587 nm). The assay is simple, direct, highly sensitive and high throughput-ready. 

Glutathione Peroxidase (GPx) plays important role in protecting organisms from oxidative damage. It converts reduced glutathione (GSH) to oxidized glutathione (GSSG), to reduce lipid hydroperoxides to their corresponding alcohols, or reduce free hydrogen peroxide to water. Several isozymes have been found in different cellular locations and with different substrate specificity. Low levels of GPx have been correlated with free radical related disorders.

PromoKine’s Glutathione Peroxidase Activity Assay Kit measures glutathione dependent peroxidase activity through a coupled reaction with glutathione reductase (GR) in different sample materials (e.g. plasma, erythrocyte lysates, tissue homogenates, cell lysates) with a high detection sensitivity. In this assay, glutathione peroxidase (GPx) reduces cumene hydroperoxide, and oxidizes GSH to GSSG. The generated GSSG is reduced to GSH with consumption of NADPH by GR. The decrease of NADPH is proportional to GPx activity and can be easily measured by absorbance at 340 nm.

Quantification of lipid peroxidation is essential to assess oxidative stress in pathophysiological processes and measuring the end products of lipid peroxidation is one of the most widely accepted assays for oxidative damage. Lipid peroxidation forms malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) as natural bi-products.

PromoKine’s Lipid Peroxidation (MDA) Assay Kit provides a convenient tool for highly sensitive detection of the MDA in a variety of samples. The MDA in the sample reacts with thiobarbituric acid (TBA) to generate the MDA-TBA adduct which can be easily quantified colorimetrically (λ = 532 nm) or fluorometrically (Ex/Em = 532/553 nm). 

Product Name Description Size Catalog Number Information Prices
Monoamine Oxidase Activity Assay Kit Fluorometric measurement of total MAO, MAO-A and MAO-B activities in various biological samples 100 assays PK-CA577-K795 click to select country
Monoamine Oxidase A (MAO-A) Inhibitor Screening Kit High-throughput fluorometric assay to screen/study/characterize potential inhibitors of monoamine oxidase A 100 assays PK-CA577-K796 click to select country
Monoamine Oxidase B (MAO-B) Inhibitor Screening Kit High-throughput fluorometric assay to screen/study/characterize potential inhibitors of monoamine oxidase B 100 assays PK-CA577-K797 click to select country
Myeloperoxidase (MPO) Activity Assay Kit I Fast, convenient and sensitive colorimetric assay for measuring MPO activity in biological samples 100 assays PK-CA577-K744 click to select country
Myeloperoxidase (MPO) Activity Assay Kit II Fast, convenient and sensitive fluorometric assay for measuring MPO activity in biological samples 100 assays PK-CA577-K745 click to select country
Myeloperoxidase (MPO) Inhibitor Screening Kit Rapid, simple and reliable fluorometric assay for screening potential inhibitors of MPO 200 assays PK-CA577-K746 click to select country
Myeloperoxidase (MPO) Peroxidation Activity Assay Kit Highly sensitive fluorometric measurement of MPO activity in various tissues/cells 100 assays PK-CA577-K747 click to select country
Xanthine Oxidase Activity Assay Kit Rapid, simple and high-throughput-adaptable colorimetric & fluorometric assay that can detect very low xanthine oxidase levels in various biological samples 100 assays PK-CA577-K710 click to select country
Glucose Oxidase Activity Assay Kit Convenient kit for sensitive detection of glucose oxidase activity in a variety of samples 100 assays PK-CA577-K788 click to select country
Lysyl Oxidase Activity Assay Kit Fast and simple fluorometric measurement of lysyl oxidase activity in various biological samples and purified proteins 100 assays PK-CA577-K928 click to select country
Peroxidase Activity Assay Kit Simple, direct, highly sensitive and high-throughput adaptable colorimetric & fluorometric assay to quantify peroxidase activity 100 assays PK-CA577-K772 click to select country
Glutathione Peroxidase Activity Assay Kit Colorimetric assay that can be used to measure all of the glutathione dependent peroxidases in different sample types with high detection sensitivity 100 assays PK-CA577-K762 click to select country
Lipid Peroxidation (MDA) Assay Kit Fast, simple and sensitive colorimetric & fluorometric assay for measuring lipid peroxidation (LPA) in a wide range of samples 100 assays PK-CA577-K739 click to select country