A drop of hydrogen peroxide is then applied to the swab. If hemoglobin is present, the hydrogen peroxide decomposes to yield oxygen that in turn oxidizes the phenolphtalin to phenolphthalein. Since the solution is basic, a pink colour develops indicating the presence of blood. The test is very sensitive, but is not specific for human blood.
Animal blood will also yield a positive reaction as will oxidizing agents such as some metal ions. The technique is to spray the suspect area with a solution of luminol and hydrogen peroxide. If blood is present, the peroxide will yield oxygen that then reacts with luminol to produce a blue glow.
This reaction was first noted in by the German chemist H. Albrecht and was put into forensic practice in by forensic scientist Walter Specht. Even dried and decomposed blood gives a positive reaction with the blue glow lasting for about 30 seconds per application.
The glow can be documented with a photo but a fairly dark room is required for detection. The reaction is so sensitive that it can reveal blood stains on fabrics even after they have been laundered.
Direct evidence of the role of EPO in the pathogenesis is scanty, despite all the above described eosinophil related diseases. Development of EPO knockout mouse line Denzler et al. Myeloperoxidase MPO is packed inside the cytoplasmic azurophilic granules of neutrophils and is involved in unspecific immune defence system responsible for microbicidal activity Kajer et al.
MPO catalyzes lipid peroxidation via tyrosyl radical formation Savenkova et al. MPO has been strongly implicated in other disease like rheumatoid arthritis, atherosclerosis and lung cancer Hoy et al.
MPO is also released from polymorphonuclear neutrophils and monocytes in acute coronary syndrome after activation and so listed as risk marker in such diseases Mocatta et al. Recent research shows that MPO is an emerging biomarker to assess cardiovascular diseases CVD and endothelial dysfunction in vivo Eiserich et al. Even though this enzyme has been used as a risk marker in this syndrome Morrow et al. There is also a strong association between carotid atherosclerosis and the MPO in patients whose HDL cholesterol levels are less than desirable value Exner et al.
It has also been observed that inherited MPO defects can lead to impaired fungicidal activity which can lead to candidiasis Cheng et al. Furthermore, MPO leads to the development of atheroma and plaque rupture as it generates reactive oxidants and radicals as well.
Several other peroxidases and related diseases have been identified, but are less characterized. These peroxidases have also some tissue specific distribution and functions. Uterine peroxidase plays an important role in oestrogen-induced uterine hyperaemia and uterine weight by conversion of oestrogen to their catechol forms Farley et al.
Several eye diseases like cataract and macular degeneration may be related with the oxidative mechanisms also, as few studies have shown that high levels of GPx are associated with age related macular degeneration Delcourt et al. These peroxidases have more or less common mechanism of action with other common peroxidases and promising research is going on in understanding their proper roles. Different types of oxyradicals once considered as harmful products are now know to perform some essential cellular functions.
But any imbalance in their production leads to varied diseases, so putting forward the burden of this stress on peroxidases as well. Peroxidases play a significant role in antioxidant defense system of living organisms and are actively involved in oxyradical oxidation, hormone biosynthesis, and innate immunity. Different peroxidases have organ, tissue, cellular or sub-cellular specificities and are directly or indirectly involved in various diseases of mankind. During different diseases, the expression of peroxidases either increases or decreases.
Several mechanisms have been suggested to explain their varied expressions during diseased states. Even though peroxidases have been used as risk markers in different human diseases but its perfect role is not yet well defined. National Center for Biotechnology Information , U. Glob J Health Sci. Published online May Amjad A. Khan , 1 Arshad H. Rahmani , 2 Yousef H. Aldebasi , 3 and Salah M. Aly 2, 4. Arshad H. Yousef H. Salah M. Author information Article notes Copyright and License information Disclaimer.
Tel: , Fax: E-mail: as. Received Apr 4; Accepted Apr This article has been cited by other articles in PMC. Abstract Peroxidases represent a family of isoenzymes actively involved in oxidizing reactive oxygen species, innate immunity, hormone biosynthesis and pathogenesis of several diseases. Introduction Reactive oxygen species ROS are constantly generated in various metabolic activities of all aerobic organisms. Peroxidases Peroxidases belong to a large family of isoenzymes present in almost all living organisms.
Open in a separate window. Figure 1. Figure 2. Selenocysteine containing Glutathione peroxidase biosynthesis model. Other Peroxidases Several other peroxidases and related diseases have been identified, but are less characterized.
Conclusion Different types of oxyradicals once considered as harmful products are now know to perform some essential cellular functions. References Atasever A. One-step purification of lactoperoxidase from bovine milk by affinity chromatography.
Food Chemistry. Lactoperoxidase: From catalytic mechanism to practical applications. International Dairy Journal. Protein disulfide isomerase and glutathione are alternative substrates in the one Cys catalytic cycle of glutathione peroxidase 7. Biochimica et Biophysica Acta. Emerging role of myeloperoxidase and oxidant stress markers in cardio-vascular risk assessment.
Current Opinions of Lipidology. Glutathione peroxidases in different stages of carcinogenesis. Glutathione peroxidase. Biochemica et Biophysica Acta. Eukaryotic initiation factor 4a3 is a selenium-regulated RNA-binding protein that selectively inhibits selenocysteine incorporation. Molecular Cell. Superoxide and hydrogen peroxide in relation to mammalian cell proliferation.
The lipid peroxidation product 4-hydroxy-2,3-nonenal increases APbinding activity through caspase activation in neurons. Journal of Neurochemistry. Roles of the glutathione- and thioredoxin-dependent reduction systems in the Escherichia coli and Saccharomyces cerevisiae responses to oxidative stress.
Annual Reviews of Microbiology. Hypothyroidism in pregnancy. Apollo Medicine. EMBO Journal. Viricidal effect of stimulated human mononuclear phagocytes on human immunodeficiency virus type 1.
Ribosomal protein L30 is a component of the UGA-selenocysteine recoding machinery in eukaryotes. Natural Structure and Molecular Biology.
GPx3 promoter hypermethylation is a frequent event in human cancer and is associated with tumorigenesis and chemotherapy response. Cancer Letters. Textile industries play a vital role in the economic increases in India. Water is one of the major products of nature used enormously by human beings, and it is not unnatural that any growing community generates enormous waste water or sewage [ 10 ].
To achieve the biodegradation of environmentally hazardous compounds, white rot fungi appear as a valuable alternative. The capability of oxidation is based on the ability of white rot fungi to produce oxidative enzymes such as laccase, manganese peroxidase, and lignin peroxidase [ 11 ].
These oxidases and peroxidases have been reported as excellent oxidant agents to degrade dyes [ 12 ]. Several bacterial peroxidases have been used for decolorization of synthetic textile dyes. AO7 was used as an electron donor by the reduction enzyme of Brevibacterium casei for the reduction of Cr VI. Decolorization of different azo dyes by Phanerochaete chrysosporium RP 78 under optimized conditions was studied [ 14 ] by reaction mechanism via azo dye.
Peroxidase was produced under aerobic conditions as a secondary metabolite in the stationary phase. Bacillus sp. VUS isolated from textile effluent contaminated soil showed capability for degrading a variety of dyes [ 15 ].
The production of ligninolytic peroxidases directly oxidizing aromatic compounds has been described in fungi [ 16 ]. Other peroxidases were detected in microorganisms responsible for the biodegradation of industrial dyes together with lignin peroxidase [ 17 ]. An edible macroscopic fungi Pleurotus ostreatus produced an extracellular peroxidase that can decolorize remazol brilliant blue and other structurally different groups including triarylmethane, heterocyclic azo, and polymeric dyes.
HRP was found to degrade industrially important azo dyes such as remazol blue. This dye contains at least one aromatic group in its structure making it a possible substrate of HRP [ 19 ]. Industrial pollution has been a major factor causing the degradation of the environment around us, affecting the water we use; its quality and human health is directly related issues. Improved quality and increased quantity of water would bring forth health benefits.
Safe water eliminates the infective agents associated with water borne diseases; availability of greater quantity of water can improve health by allowing improved personal hygiene. Water pollution caused industrial waste products to release into lakes, rivers, and other water bodies that make marine life no longer hospitable.
Peroxidases have been applied to the bioremediation of waste waters contaminated with phenols, cresols, and chlorinated phenols [ 2 , 9 ]. Aromatic compounds including phenols and aromatic amines constitute one of the major classes of pollutants. They are found in the waste waters of a wide variety of industries, including coal conversion, petroleum refining, resins and plastics, wood preservation, metal coating, dyes and other chemicals, textiles, mining and dressing, and pulp and paper industries [ 34 ].
Phenols and halogenated phenols present in textile industries processed water are known to be toxic and also some of them are hazardous carcinogens that can accumulate in the food chain [ 5 ]. Peroxidases comprise an important class of enzymes able to catalyze the oxidative coupling reactions of a broad range of phenolic compounds [ 35 ]. Lignin peroxidase from Phanerochaete chrysosporium , HRP, myeloperoxidase, lactoperoxidase, microperoxidase-8, a versatile peroxidase from Bjerkandera adusta , and chloroperoxidase from Caldariomyces fumago [ 36 ] were able to transform pentachlorophenol totetrachloro-1,4-benzoquinone by an oxidative dehalogenation in the presence of H 2 O 2.
An extracellular manganese peroxidase produced by P. Many toxic aromatic and aliphatic compounds occur in waste water of a number of industries. Among these, phenol is the most common aromatic pollutant and is also found in contaminated drinking water.
Phenol can be toxic when present at an elevated level and is known to be carcinogenic. It has an effect on health even at low concentration. A laboratory phenol was treated with turnip root enzyme peroxidase extract in the presence of H 2 O 2 as an oxidant to form corresponding free radicals.
Free radicals polymerize to form substances that are less soluble in water. The precipitates were removed by centrifugation and residual phenol was estimated [ 38 ]. The results showed that turnip root enzyme extract degraded phenol more efficiently. Another versatile peroxidase produced by P. Horseradish peroxidase undergoes a cyclic reaction when reacting with phenolic substrates.
This sequence is summarized in the following reactions: The enzyme starts in its native form E and is oxidized by H 2 O 2 to form an active intermediate compound known as compound 1 Ei. Compound II oxidizes a second phenol molecule to produce another phenol free radical and complete the cycle by returning to its native form E. The free radicals polymerize and form insoluble compounds which precipitate from solution [ 40 ]. Several classes of oxidative enzymes have shown promise for efficient removal of EDCs that are resistant to conventional waste water treatments.
Although the kinetics of reactions between individual EDCs and selected oxidative enzymes such as HRP are well documented in the literature, there has been little investigation of reactions with EDC mixtures [ 41 ]. EDCs are a group of compounds that due to their chemical structure are able to act as agonists or antagonists of hormones. They can disturb the synthesis, secretion, transport, binding, action, and elimination of the endogenous hormones, which are responsible for maintaining homeostasis, reproduction, development, and integrity in living organisms and their progeny [ 42 ].
They are widely dispersed in the environment but are mainly found in waste water effluents. Several works reported the EDC oxidation by manganese peroxidase.
Peroxidases are also helpful in removal or degradation of other potent environmental pollutants such as chloroanilines and polycyclic aromatic hydrocarbons [ 44 ]. Pesticides include a broad range of substances most commonly used to control insects, weeds, and fungi. Pesticide exposure in human is associated with chronic health problems or health symptoms such as respiratory problems, memory disorders, dermatologic conditions, cancer, depression, neurologic deficits, miscarriages, and birth defects [ 45 ].
Biological decomposition of pesticides is the most important and effective way to remove these compounds from the environment. Microorganisms have the ability to interact, both chemically and physically, with substances leading to structural changes or complete degradation of the target molecule [ 46 ]. Peroxidases extracted from some fungal species have great potential to transform several pesticides into harmless form s.
Transformation of organophosphorus pesticides by white rot fungi has been studied [ 47 ], and transformation of several organophosphorus pesticides by the chloroperoxidase from Caldariomyces fumago has been reported. PAHs are composed of two or more fused aromatic rings and are components of crude oil, creosote, and coal [ 48 ]. Most of the contamination by PAHs had originated from the extensive use of fossil fuels as energy sources.
PAHs are oxidized by peroxidases such as lignin peroxidase [ 49 ] and manganese peroxidase [ 50 ]. In spite of their versatility and potential use in environmental processes, peroxidases are not applied at large scale yet. Diverse challenges, such as stability, redox potential, and the production of large amounts, should be addressed in order to apply peroxidases in the pollutant transformation [ 51 ].
Diverse challenges, such as stability, redox potential, and the production of large amounts, should be addressed in order to apply peroxidases in the pollutant transformation. Contamination of soils and aquifers by the aliphatic halocarbons trichloroethylene TCE and perchloroethylene PCE widely used as degreasing solvents is a serious environmental pollution problem.
This strain also showed the capability to degrade other imidazolinone herbicides such as imazapyr, imazapic, and imazamox [ 53 ]. Extracellular hydroxyl radicals produced by T. TCE is mineralized by P. The most commonly used broad leaf herbicides around the world are 2,4-dichlorophenoxyacetic acid 2,4-D and 2,4,5-trichlorophenoxyaceticacid 2,4,5-T. On other hand 2,4,5-T is relatively more resistant to microbial degradation and tends to persist in the environment. It has been blamed for serious illnesses in many veterans of Vietnam War, where they got exposed to Agent Orange that was used as a defoliant.
These were also reported to be mutagenic agents and thus very toxic to humans. Ligninolytic peroxidases of P. These results were based on the increased degradation of ring-labeled and side chain-labeled 2,4,5-T and 2,4-D by D. Atrazine is a commonly used triazine herbicide and is degraded by a number of white rot fungi produced laccases and peroxidase [ 54 ]. Polychlorinated dibenzodioxins PCDDs are a group of highly toxic environmental pollutants that are confirmed human carcinogens and tend to bioaccumulate in humans and animals due to their lipophilic properties.
A fungus P. Lindane c isomer of hexachlorocyclohexane was a widely used pesticide in the past, and an estimated , tons of lindane were produced globally between the year and There is a global ban on the use of lindane now because of its environmental persistence as a pollutant.
DDT 1,1,1-trichloro-2,2-bis [4-chlorophenyl] ethane , the first of the chlorinated organic insecticides, was used quite heavily after World War II. High levels of DDT found in agricultural soils are of deep concern, because they present serious threats to food security and human health. The white rot fungi P. Biosensors have been defined as analytical devices which tightly combine biorecognition elements with physical transducers for detection of the target compound.
Several examples of biosensors developed for relevant environmental pollutants. Biosensors can be useful, for example, for the continuous monitoring of a contaminated area [ 59 ]. They may also present advantageous analytical features, such as high specificity and sensitivity inherent in the particular biological recognition bioassay.
Due to its crucial role in neurochemistry, determination of the concentration of H 2 O 2 has been a considerable interesting research field. Electrochemical methods based on peroxidase biosensors have proved to be significantly advantageous to the biosciences due to their direct real-time measurements and capability for practical applications [ 60 ]. A novel third generation biosensor for hydrogen peroxide was constructed by cross-linking HRP onto an electrode modified with multiwall carbon nanotubes [ 61 ].
At the same time, biosensors offer the possibility of determining not only specific chemicals but also their biological effects, such as toxicity, cytotoxicity, genotoxicity, or endocrine disrupting effects, that is, relevant information that in some occasions is more meaningful than the chemical composition.
Enzymatic biosensors are based on the selective inhibition of specific enzymes by different classes of compounds, with the decrease in activity of the immobilized enzyme in the presence of the target analyte as the parameter that is frequently used for quantification.
The histidine and asparagine residues on the distal side of the heme make the environment strongly hydrophobic [ 30 ]. Despite possessing the same type of heme in active site, PVC and HPII differ in the presence of covalent bond between tyrosine and histidine residues. The limited accessibility to heme grouping catalases requires the presence of channels [ 30 ].
The heme of the enzyme is connected to the exterior surface by three channels, namely, the main channel, the lateral channel, and the central channel. Among them, the main channel is placed perpendicular to the surface of the heme.
The lateral channel approaches horizontal to the heme and the central one heading from the distal side [ 34 , 45 ]. The main channel is considered to be the primary route for substrate movement to the active site [ 1 , 3 ]. The role of aspartate has not been investigated in any catalase, but the presence of negatively charged side chain has been found to be critical for catalysis [ 45 ].
The lateral or minor channel approaches heme above and below the essential asparagine and emerges in the molecular surface at location corresponding to the NADP H -binding pocket in catalases that bind a cofactor Figure 4 [ 30 , 50 ]. The function of this channel remains unknown [ 34 ]. Molecular dynamics analysis indicates that water can exit the protein through this channel [ 4 ]. The main channel is a preferred route for substrate entry, but it might be too long and narrow for the release of reaction products water and molecular oxygen.
As the central channel is mainly hydrophilic and leads to the central cavity that is contiguous to the bulk water, this could be a way out for O 2.
However, substitutions of amino acid residues extending the major channel in large catalases might allow the exit of oxygen through the main channel. In fact, oxygen preferentially exits through the main channel instead of central one in all catalases having b-type heme in the active site. Thus, the presence of minor channels might be an alternative mechanism for a fast release of products under the condition of high H 2 O 2 stress. These results indicate that O 2 can exit the enzyme through different channels although the main exit in large catalases might be through the central channel and in small catalases through the major channel [ 34 , 51 ].
Many reports on catalase and phenol oxidase enzymes suggest that the activities may flap in some way that catalases exhibit additional oxidase activity and phenol oxidases present further catalase activity. This relationship can be explained by the release of H 2 O 2 due to polyphenol oxidation [ 52 ]. Hydrogen peroxide generation by phenol oxidation was also reported by Aoshima and Ayebe [ 53 ].
They observed high concentrations of H 2 O 2 in beverages like tea or coffee directly after opening caps as a result of oxygen. Jolley et al. Garcia-Molina et al.
In addition to this novel tyrosinase, a catalase-like process was found to have one isozyme of catechol oxidase from sweet potatoes Ipomoea batatas [ 57 ]. In literature, the first report on catalase known as a monofunctional enzyme but possessing secondary activity oxidase was introduced for mammalian catalase. This enzyme has been reported to present oxidase activity when hydrogen peroxide is absent or levels of H 2 O 2 are low.
As mentioned previously, the main function of catalase is the decomposition of hydrogen peroxide into water and oxygen catalytic activity. Moreover, it is known that catalases can oxidize low molecular weight alcohols in the presence of low concentrations of H 2 O 2 peroxidatic activity.
The peroxidase activity stems from the oxidation of alcohols by compound I through single-electron transfer. This oxidase reaction involves the interaction of catalase heme with a strong reducing agent like benzidine HB and molecular oxygen leading to the formation of a compound II-like intermediate.
The subsequent electron transfer causes substrate oxidation and regeneration of resting enzyme. An incomplete reaction may result in the formation of radical centered intermediates and the production of superoxide [ 14 ]. Later, catalase from the thermophilic fungus S. This enzyme, named as CATPO, is the first bifunctional catalase-phenol oxidase in the literature that is characterized in detail.
CATPO can oxidize o -diphenols such as catechol, caffeic acid, and L-DOPA in the absence of hydrogen peroxide, and the highest oxidase activity is observed against catechol. This enzymatic activity is oxygen-dependent and is inhibited by classic catalase inhibitors, including 3-amino-1,2,4-triazole 3TR.
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