query: hydrogen peroxide is the substrate for which enzyme

pos: Substrate (chemistry) substrate. Another example is the chemical decomposition of hydrogen peroxide carried out by the enzyme catalase. As enzymes are catalysts, they are not changed by the reactions they carry out. The substrate(s), however, is/are converted to product(s). Here, hydrogen peroxide is converted to water and oxygen gas. While the first (binding) and third (unbinding) steps are, in general, reversible, the middle step may be irreversible (as in the rennin and catalase reactions just mentioned) or reversible (e.g. many reactions in the glycolysis metabolic pathway). By increasing the substrate concentration, the rate of reaction will increase due to the likelihood that

pos: Chloride peroxidase Chloride peroxidase Chloride peroxidase () is a family of enzymes that catalyzes the chlorination of organic compounds. This enzyme combines the inorganic substrates chloride and hydrogen peroxide to produce the equivalent of Cl, which replaces a proton in hydrocarbon substrate: Many organochlorine compounds are biosynthesized in this way. This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptors (peroxidases). The systematic name of this enzyme class is chloride:hydrogen-peroxide oxidoreductase. This enzyme is also called chloroperoxidase. It employs one cofactor which may be either heme or vanadium. The heme-containing chloroperoxidase (CPO) exhibits peroxidase, catalase and

pos: Enzyme kinetics an RNA lyase. However, some enzymes that only have a single substrate do not fall into this category of mechanisms. Catalase is an example of this, as the enzyme reacts with a first molecule of hydrogen peroxide substrate, becomes oxidised and is then reduced by a second molecule of substrate. Although a single substrate is involved, the existence of a modified enzyme intermediate means that the mechanism of catalase is actually a ping–pong mechanism, a type of mechanism that is discussed in the "Multi-substrate reactions" section below. As enzyme-catalysed reactions are saturable, their rate of catalysis does not show a

pos: Hydrogen peroxide biologically by the enzyme catalase. The decomposition of hydrogen peroxide liberates oxygen and heat; this can be dangerous, as spilling high-concentration hydrogen peroxide on a flammable substance can cause an immediate fire. Hydrogen peroxide exhibits oxidizing and reducing properties, depending on pH. In acidic solutions, is one of the most powerful oxidizers known, when used for removing organic stains from laboratory glassware it is referred to as Piranha solution and is stronger than chlorine, chlorine dioxide, and potassium permanganate. Also, through catalysis, can be converted into hydroxyl radicals (·OH), which are highly reactive. In acidic solutions is oxidized to (hydrogen

pos: Antioxidant peroxide is its only substrate, it follows a ping-pong mechanism. Here, its cofactor is oxidised by one molecule of hydrogen peroxide and then regenerated by transferring the bound oxygen to a second molecule of substrate. Despite its apparent importance in hydrogen peroxide removal, humans with genetic deficiency of catalase — "acatalasemia" — or mice genetically engineered to lack catalase completely, suffer few ill effects. Peroxiredoxins are peroxidases that catalyze the reduction of hydrogen peroxide, organic hydroperoxides, as well as peroxynitrite. They are divided into three classes: typical 2-cysteine peroxiredoxins; atypical 2-cysteine peroxiredoxins; and 1-cysteine peroxiredoxins. These enzymes share the same

pos: Malcolm Dixon and thereby elucidated many aspects of the chemistry of dehydrogenases. He showed that the hydrogen peroxide formed in the reaction of xanthine oxidase with molecular oxygen inactivated the enzyme and that the inhibition could be relieved by the addition of catalase, thus helping to establish a biochemical role for the latter enzyme. Dixon published a series of papers on D-amino acid oxidase, detailing the kinetics and thermodynamics of association of the coenzyme with the apoprotein, the substrate and inhibitor specificity, and the effect of pH on the kinetic constants. Dixon was an expert on the theory and use of manometers.

pos: Acatalasia Acatalasia Acatalasia (also called acatalasemia, or Takahara's disease) is an autosomal recessive peroxisomal disorder caused by absent or very low levels of the enzyme catalase. Catalase breaks down hydrogen peroxide in cells into water and oxygen. Low levels of catalase can cause hydrogen peroxide to build up, causing damage to cells. The disorder is relatively benign, although it causes an increased incidence of oral ulcers, and can under rare circumstances lead to gangrene. Symptoms primary affect children. Acatalasia is often the result of mutations in both copies of the CAT gene which codes for the enzyme catalase. There are multiple

pos: Diagnostic microbiology lysed by sodium deoxycholate. Lysis indicates "S. Pneumoniae" while no lysis does not. A CAMP test is used to differentiate between "Streptococcus agalactiae" and other species of beta-hemolytic "Streptococcus." This biochemical test uses the fact that "Streptococcus agalactiae" excretes a CAMP substance, making it slightly more hemolytic, which can be observed on blood agar media. The catalase test tests whether a microbe produce the enzyme catalase, which catalyzes the breakdown of hydrogen peroxide. Smearing a colony sample onto a glass slide and adding a solution of hydrogen peroxide will indicate whether the enzyme is present or not. Bubbling is a

pos: Hydrogen peroxide produce hydrogen peroxide in the following process: Catalase, another peroxisomal enzyme, uses this HO to oxidize other substrates, including phenols, formic acid, formaldehyde, and alcohol, by means of the peroxidation reaction: This reaction is important in liver and kidney cells, where the peroxisomes neutralize various toxic substances that enter the blood. Some of the ethanol humans drink is oxidized to acetaldehyde in this way. In addition, when excess HO accumulates in the cell, catalase converts it to HO through this reaction: Another origin of hydrogen peroxide is the degradation of adenosine monophosphate which yields hypoxanthine. Hypoxanthine is then oxidatively catabolized

pos: Hydrogen peroxide proteins, membrane lipids and DNA by the peroxide ions. The class of biological enzymes called SOD (superoxide dismutase) is developed in nearly all living cells as an important antioxidant agent. They promote the disproportionation of superoxide into oxygen and hydrogen peroxide, which is then rapidly decomposed by the enzyme catalase to oxygen and water. Peroxisomes are organelles found in virtually all eukaryotic cells. They are involved in the catabolism of very long chain fatty acids, branched chain fatty acids, -amino acids, polyamines, and biosynthesis of plasmalogens, etherphospholipids critical for the normal function of mammalian brains and lungs. Upon oxidation, they

pos: Catalase negative results. The opposite end is then dipped into hydrogen peroxide, which is drawn into the tube through capillary action, and turned upside down, so that the bacterial points downwards. The hand holding the tube is then tapped on the bench, moving the hydrogen peroxide down until it touches the bacteria. If bubbles form on contact, this indicates a positive catalase result. This test can detect catalase-positive bacteria at concentrations above about 10 cells/mL, and is simple to use. Neutrophils and other phagocytes use peroxide to kill bacteria. The enzyme NADPH oxidase generates superoxide within the phagosome, which is converted

pos: Azotobacter salinestris were not affected by the presence of oxygen. "A. salinestris" that grows in soils is a facultative anaerobe. Colonies growing in aquatic habitats were determined to be microaerophilic and very sensitive to the presence of hydrogen peroxide since they do not produce a catalase enzyme. "A. salinestris" can use melibiose, galactose, mannitol, sucrose, glucose, and fructose as primary carbon sources. They prefer to use sodium ions as their electron acceptor, but also use rubidium. Strains that do not have access to sodium ions produce acid as a product of the metabolism of their growth-promoting carbon substrate. All known "A. salinestris"

pos: Catalase heart, and kidneys of mice. Catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals). It catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Likewise, catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second. Catalase is a tetramer of four polypeptide chains, each over 500 amino acids long. It contains four

pos: Catalase Catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals). It catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Likewise, catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second. Catalase is a tetramer of four polypeptide chains, each over 500 amino acids long. It contains four iron-containing heme groups that allow

pos: Chronic granulomatous disease in people with normal immune systems. Among the most common organisms that cause disease in CGD patients are: Patients with CGD can usually resist infections of catalase-negative bacteria but are susceptible to catalase-positive bacteria. Catalase is an enzyme that catalyzes the breakdown of hydrogen peroxide in many organisms. In infections caused by organisms that lack catalase (catalase-negative), the host with CGD is successfully able to "borrow" hydrogen peroxide being made by the organism and use it to fight off the infection. In infections by organisms that have catalase (catalase-positive), this "borrowing mechanism" is unsuccessful because the enzyme catalase first breaks

pos: Photorespiration peroxisome where it is converted into glycerate. Glycerate reenters the chloroplast and by the same transporter that exports glycolate. A cost of 1 ATP is associated with conversion to 3-phosphoglycerate (PGA) (Phosphorylation), within the chloroplast, which is then free to re-enter the Calvin cycle. There are several costs associated with this metabolic pathway; one being the production of hydrogen peroxide in the peroxisome (associated with the conversion of glycolate to glyoxylate). Hydrogen peroxide is a dangerously strong oxidant which must be immediately broken down into water and oxygen by the enzyme catalase. The conversion of 2× 2Carbon glycine to 1

pos: Superoxide dismutase Superoxide dismutase Superoxide dismutase (SOD, ) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O) radical into either ordinary molecular oxygen (O) or hydrogen peroxide (HO). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. Hydrogen peroxide is also damaging and is degraded by other enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen. One exception is "Lactobacillus plantarum" and related lactobacilli, which use a different mechanism to prevent damage from reactive (O). SODs catalyze

pos: Euprymna scolopes as a substrate, but "A. fischeri" has evolved a brilliant counterattack. "A. fischeri" possesses a periplasmic catalase that captures hydrogen peroxide before it can be used by the squid halide peroxidase, thus inhibiting the enzyme indirectly. Once through these ciliated ducts, "A. fischeri" cells swim on towards the antechamber, a large epithelial-lined space, and colonize the narrow epithelial crypts. The bacteria thrive on the host-derived amino acids and sugars in the antechamber and quickly fill the crypt spaces within 10 to 12 hours after hatching. Every second, a juvenile squid ventilates about of ambient seawater through its mantle cavity. Only

pos: Human hair color to activate well over a decade before those in adjacent follicles less than a millimeter apart. Graying of hair may be triggered by the accumulation of hydrogen peroxide and abnormally low levels of the enzyme catalase, which breaks down hydrogen peroxide and relieves oxidative stress in patients suffering from vitiligo. Since vitiligo can cause eyelashes to turn white, the same process is believed to be involved in hair on the head (and elsewhere) due to aging. The anti-cancer drug imatinib has recently been shown to reverse the graying process. However, it is expensive and has potentially severe and deadly side

pos: Malate oxidase inhibition of corrosion by dissolved oxygen in water by converting it to hydrogen peroxide, which is subsequently broken down into water and oxygen by catalase. Malate oxidase In enzymology, a malate oxidase () is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are (S)-malate and O, whereas its two products are oxaloacetate and HO. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with oxygen as acceptor. The systematic name of this enzyme class is (S)-malate:oxygen oxidoreductase. Other names in common use include FAD-dependent malate oxidase,

pos: Phenotypic testing of mycobacteria by heating at 68°C for 20 minutes (others are stable). Organisms producing the enzyme catalase have the ability to decompose hydrogen peroxide into water and free oxygen. The test differs from that used to detect catalase in other types of bacteria by using 30% hydrogen peroxide in a strong detergent solution (10% polysorbate 80). Sole carbon source Growth on Löwenstein–Jensen medium (LJ medium) Sole carbon and nitrogen source The growth rate is the length of time required to form mature colonies visible without magnification on solid media. Mycobacteria forming colonies visible to the naked eye within seven days on subculture

pos: Coordination complex estimated 30% of proteins contain metal ions. Examples include the intensely colored vitamin B, the heme group in hemoglobin, the cytochromes, and the chlorin group in chlorophyll. Carboxypeptidase, a hydrolytic enzyme important in digestion. Another complex ion enzyme is catalase, which decomposes the cell's waste hydrogen peroxide. Homogeneous catalysis is a major application of coordination compounds for the production of organic substances. Processes include hydrogenation, hydroformylation, oxidation. In one example, a combination of titanium trichloride and triethylaluminium gives rise to Ziegler-Natta catalysts, used for the polymerization of ethylene and propylene to give polymers of great commercial importance as fibers, films,

neg: Malate oxidase and a chemiluminescent dye are used in disease detecting systems. The biomarker activates the malate oxidase to generate hydrogen peroxide that excites the light-emitting dye, which exhibits chemiluminescence in the presence of the peroxide. Such contemporary compositions are thus used as a diagnostic tool for detecting diseases. In a similar method, malate oxidase is used in the transcutaneous measurement of the amount of a substrate in blood. The method is conducted by contacting the skin with the enzyme, reacting the substrate with the enzyme and directly detecting the amount of HO produced as a measure of the amount of substrate

neg: Malate oxidase in the blood, with use of a hydrogen peroxide electrode. Further dermatological applications are in drugs or cosmetic agents, comprising a suitable substrate and malate oxidase as hydrogen peroxide producing enzyme for skin lightening and age spots or freckles. Other illustrative uses that employ the capacity of malate oxidase to yield hydrogen peroxide in the presence of a suitable substrate, including malate, are found in toothpaste to remove bacterial plaque, cleaning compositions for removing blood stains and the like, and in the removal of chewing gum lumps stuck on surfaces by enzymatic degradation. Malate oxidase is also employed in the

neg: Chloride peroxidase , and . Chloride peroxidase Chloride peroxidase () is a family of enzymes that catalyzes the chlorination of organic compounds. This enzyme combines the inorganic substrates chloride and hydrogen peroxide to produce the equivalent of Cl, which replaces a proton in hydrocarbon substrate: Many organochlorine compounds are biosynthesized in this way. This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptors (peroxidases). The systematic name of this enzyme class is chloride:hydrogen-peroxide oxidoreductase. This enzyme is also called chloroperoxidase. It employs one cofactor which may be either heme or vanadium. The heme-containing chloroperoxidase (CPO) exhibits

neg: Glutathione peroxidase Glutathione peroxidase Glutathione peroxidase (GPx) () is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage. The biochemical function of glutathione peroxidase is to reduce lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. Several isozymes are encoded by different genes, which vary in cellular location and substrate specificity. Glutathione peroxidase 1 (GPx1) is the most abundant version, found in the cytoplasm of nearly all mammalian tissues, whose preferred substrate is hydrogen peroxide. Glutathione peroxidase 4 (GPx4) has a high preference for

neg: Lactoperoxidase Lactoperoxidase Lactoperoxidase is a peroxidase enzyme secreted from mammary, salivary, and other mucosal glands that functions as a natural antibacterial agent. Lactoperoxidase is a member of the heme peroxidase family of enzymes. In humans, lactoperoxidase is encoded by the "LPO" gene. Lactoperoxidase catalyzes the oxidation of a number of inorganic and organic substrates by hydrogen peroxide. These substrates include bromide and iodide and therefore lactoperoxidase can be categorised as a haloperoxidase. Another important substrate is thiocyanate. The oxidized products produced through the action of this enzyme have potent bactericidal activities. Lactoperoxidase together with its inorganic ion substrates, hydrogen peroxide, and

neg: Phagocyte The superoxide is converted to hydrogen peroxide and singlet oxygen by an enzyme called superoxide dismutase. Superoxides also react with the hydrogen peroxide to produce hydroxyl radicals, which assist in killing the invading microbe. The second type involves the use of the enzyme myeloperoxidase from neutrophil granules. When granules fuse with a phagosome, myeloperoxidase is released into the phagolysosome, and this enzyme uses hydrogen peroxide and chlorine to create hypochlorite, a substance used in domestic bleach. Hypochlorite is extremely toxic to bacteria. Myeloperoxidase contains a heme pigment, which accounts for the green color of secretions rich in neutrophils, such as

neg: Chemiluminescence as translational energy. Enhanced chemiluminescence is a common technique for a variety of detection assays in biology. A horseradish peroxidase enzyme (HRP) is tethered to an antibody that specifically recognizes the molecule of interest. This enzyme complex then catalyzes the conversion of the enhanced chemiluminescent substrate into a sensitized reagent in the vicinity of the molecule of interest, which on further oxidation by hydrogen peroxide, produces a triplet (excited) carbonyl, which emits light when it decays to the singlet carbonyl. Enhanced chemiluminescence allows detection of minute quantities of a biomolecule. Proteins can be detected down to femtomole quantities, well below

neg: ABTS hydrogen peroxide-producing enzyme, or to simply quantify the amount of hydrogen peroxide in a sample. The formal reduction potentials for ABTS are high enough for it to act as an electron donor for the reduction of oxo species such as molecular oxygen and hydrogen peroxide, particularly at the less-extreme pH values encountered in biological catalysis. Under these conditions, the sulfonate groups are fully deprotonated and the mediator exists as a dianion. This compound is chosen because the enzyme facilitates the reaction with hydrogen peroxide, turning it into a green and soluble end-product. Its new absorbance maximum of 420 nm light

neg: Dehydrogenase remove electrons from a substrate as well, but only uses oxygen as its electron acceptor. One such reaction is: AH + O ↔ A + HO. Sometimes an oxidase reaction will look like this: 4A + 4H + O ↔ 4A + 2HO. In this case, the enzyme is taking electrons from the substrate, and using free protons to reduce the oxygen, leaving the substrate with a positive charge. The product is water, instead of hydrogen peroxide as seen above. An example of an oxidase that functions like this is complex IV in the Electron Transport Chain (ETC). Note that

neg: Haem peroxidase Haem peroxidase Haem peroxidases (or heme peroxidases) are haem-containing enzymes that use hydrogen peroxide as the electron acceptor to catalyse a number of oxidative reactions. Most haem peroxidases follow the reaction scheme: In this mechanism, the enzyme reacts with one equivalent of HO to give [Fe=O]R' (compound I). This is a two-electron oxidation/reduction reaction in which HO is reduced to water and the enzyme is oxidized. One oxidizing equivalent resides on iron, giving the oxyferryl intermediate, and in many peroxidases the porphyrin (R) is oxidized to the porphyrin pi-cation radical (R'). Compound I then oxidizes an organic substrate to give

neg: Antioxidant and do not require it in their diets. Ascorbic acid is required for the conversion of the procollagen to collagen by oxidizing proline residues to hydroxyproline. In other cells, it is maintained in its reduced form by reaction with glutathione, which can be catalysed by protein disulfide isomerase and glutaredoxins. Ascorbic acid is a redox catalyst which can reduce, and thereby neutralize, reactive oxygen species such as hydrogen peroxide. In addition to its direct antioxidant effects, ascorbic acid is also a substrate for the redox enzyme ascorbate peroxidase, a function that is particularly important in stress resistance in plants. Ascorbic

neg: ABTS damage by free radicals. The antioxidant potency of plant extract or food product has been measured by ABTS assay. One example with detailed method is the antioxidant activity analysis of Hibiscus products. ABTS In biochemistry, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS is a chemical compound used to observe the reaction kinetics of specific enzymes. A common use for it is in the enzyme-linked immunosorbent assay (ELISA) to detect for binding of molecules to each other. It is commonly used as a substrate with hydrogen peroxide for a peroxidase enzyme (such as horseradish peroxidase) or alone with blue multicopper oxidase enzymes (such as

neg: ABTS ABTS In biochemistry, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS is a chemical compound used to observe the reaction kinetics of specific enzymes. A common use for it is in the enzyme-linked immunosorbent assay (ELISA) to detect for binding of molecules to each other. It is commonly used as a substrate with hydrogen peroxide for a peroxidase enzyme (such as horseradish peroxidase) or alone with blue multicopper oxidase enzymes (such as laccase or bilirubin oxidase). Its use allows the reaction kinetics of peroxidases themselves to be followed. In this way it also can be used to indirectly follow the reaction kinetics of any

neg: 3,3',5,5'-Tetramethylbenzidine 3,3',5,5'-Tetramethylbenzidine 3,3’,5,5’-Tetramethylbenzidine or TMB is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays (ELISA). TMB is a white crystal powder that forms a pale blue-green liquid in solution with ethyl acetate. TMB is degraded by sunlight and by fluorescent lights. TMB can act as a hydrogen donor for the reduction of hydrogen peroxide to water by peroxidase enzymes such as horseradish peroxidase. The resulting diimine causes the solution to take on a blue colour, and this colour change can be read on a spectrophotometer at the wavelengths

neg: Peroxidase Peroxidase Peroxidases (EC number 1.11.1.x) are a large family of enzymes which play a role in various biological processes. Peroxidases typically catalyze a reaction of the form: 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. The nature of the electron donor is very dependent on the structure of the enzyme. The glutathione peroxidase family consists of 8 known human isoforms. Glutathione peroxidases use glutathione as an electron donor

neg: Superoxide reductase Superoxide reductase Superoxide reductase is an enzyme that catalyzes the conversion of highly reactive and toxic superoxide (O) into less toxic hydrogen peroxide (HO): Hydrogen peroxide in turn is reduced to water by rubrerythrin. The 3 substrates of this enzyme are reduced rubredoxin, superoxide, and H, whereas its two products are rubredoxin and HO. This enzyme belongs to the family of oxidoreductases, specifically those acting on superoxide as acceptor (only sub-subclass identified to date). The systematic name of this enzyme class is rubredoxin:superoxide oxidoreductase. Other names in common use include neelaredoxin, and desulfoferrodoxin. , 9 structures have been solved for

neg: Hydrogen peroxide first to xanthine and then to uric acid, and the reaction is catalyzed by the enzyme xanthine oxidase: The degradation of guanosine monophosphate yields xanthine as an intermediate product which is then converted in the same way to uric acid with the formation of hydrogen peroxide. Eggs of sea urchin, shortly after fertilization by a sperm, produce hydrogen peroxide. It is then quickly dissociated to OH· radicals. The radicals serve as initiator of radical polymerization, which surrounds the eggs with a protective layer of polymer. The bombardier beetle has a device which allows it to shoot corrosive and foul-smelling bubbles

neg: Superoxide reductase this class of enzymes, with PDB accession codes , , , , , , , , and . Superoxide reductase Superoxide reductase is an enzyme that catalyzes the conversion of highly reactive and toxic superoxide (O) into less toxic hydrogen peroxide (HO): Hydrogen peroxide in turn is reduced to water by rubrerythrin. The 3 substrates of this enzyme are reduced rubredoxin, superoxide, and H, whereas its two products are rubredoxin and HO. This enzyme belongs to the family of oxidoreductases, specifically those acting on superoxide as acceptor (only sub-subclass identified to date). The systematic name of this enzyme class is

neg: Fungal extracellular enzyme activity that use a 4-methylumbelliferone (MUF)-linked substrate. Oxidative enzymes such as phenol oxidase and peroxidase mediate lignin degradation and humification. Phenol oxidase activity is quantified by oxidation of L-3, 4-dihydoxyphenylalanine (L-DOPA), pyrogallol (1, 2, 3-trihydroxybenzene), or ABTS (2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid). Peroxidase activity is measured by running the phenol oxidase assay concurrently with another assay with L-DOPA and hydrogen peroxide (H2O2) added to every sample. The difference in measurements between the two assays is indicative of peroxidase activity. With newer technologies available, molecular methods to quantify abundance of enzyme-coding genes are used to link enzymes with their producers in soil environments.

neg: Ramlibacter tataouinensis availability of water confers "Ramlibacter tataouinensis" with limiting substrate i.e. water which may stimulate cell growth and division. Reactive oxygen species (ROS) are highly volatile and can damage living cells. Superoxide, an example of a ROS, can be transformed into less harmful molecules i.e. oxygen and hydrogen peroxide by an enzyme called superoxide dismutase. "Ramlibacter tataouinensis" possesses two forms of superoxide dismutase, one existing in the cytoplasm and the other in periplasm. "Ramlibacter tataouinensis" has genes encoding for carotenoid biosynthesis. Carotenoid are photosynthetic pigments usually found in chloroplasts of plants and in photosynthetic organisms like algae and fungus. These pigments

neg: Urate oxidase 228 of the enzyme. Oxygen will subsequently accept an electron pair from the uric acid dianion and be converted to hydrogen peroxide, which is replaced by water that performs a nucleophilic attack on the intermediate to produce 5-hydroxyisourate. Urate oxidase is known to be inhibited by both cyanide and chloride ions. This occurs because of anion-π interactions between the inhibitor and the uric acid substrate. Urate oxidase is found in nearly all organisms, from bacteria to mammals, but is inactive in humans and several other great apes, having been lost in early primate evolution. This means that instead of producing

neg: Haloperoxidase becomes damaged during turnover. A specific vanadium bromoperoxidase in marine organisms (fungi, bacteria, microalgae, perhaps other eukaryotes) uses vanadate and hydrogen peroxide to brominate electrophilic organics. Murex snails have a bromoperoxidase used to produce Tyrian purple dye. The enzyme is very specific to bromide and physically stable, but has not been characterized as to its active site. Haloperoxidase Haloperoxidases are peroxidases that are able to mediate the oxidation of halides by hydrogen peroxide. Both halides and hydrogen peroxide are widely available in the environment. The Nernst equation shows that hydrogen peroxide can oxidize chloride (E°= 1.36 V), bromide (E°= 1.09

neg: Vitamin C contributing to the more severe symptoms of scurvy. More generally, the biochemical role of vitamin C is to act as an antioxidant (a reducing agent) by donating electrons to various enzymatic and non-enzymatic reactions. Doing so converts vitamin C to an oxidized state - either as semidehydroascorbic acid or dehydroascorbic acid. These compounds can be restored to a reduced state by glutathione and NADPH-dependent enzymatic mechanisms. In plants, vitamin C is a substrate for ascorbate peroxidase. This enzyme utilizes ascorbate to neutralize toxic hydrogen peroxide (HO) by converting it to water (HO). Scurvy is a disease resulting from a deficiency

neg: Cannabidiolic acid synthase the production of cannabidiolate predominantly from cannabigerolate by stereospecific oxidative cyclization of the geranyl group of cannabigerolic acid according to the following chemical reaction: Cannabinerolate can also be used as a substrate, but with lower efficiency (K=0.137 mM) than cannabigerolate (K=0.206 mM). It covalently binds FAD, and does not require coenzymes, molecular oxygen, hydrogen peroxide, or metal ion cofactors for the oxidocyclization reaction. The optimum pH for CBDA synthase is 5.0. Cannabidiolic acid synthase Cannabidiolic acid synthase (, "CBDA synthase") is an enzyme with systematic name "cannabigerolate:oxygen oxidoreductase (cyclizing, cannabidiolate-forming)". It is an oxidoreductase found in "Cannabis sativa" that catalyses

neg: Skin whitening ligand but do not cleave the extracellular terminal. Several species of fungi produce enzymes that reduce pigmentation by degrading melanin. These enzymes often require the presence of hydrogen peroxide and sometimes the presence of Mg ions to work. They have been proposed as a safer alternative to hydrogen peroxide for cosmetic hair depigmentation. The enzyme lignin peroxidase produced by the fungus phanerochaete chrysosporium has been studied as an ingredient suitable for skin-whitening: A double-blind placebo-controlled split-face randomized study found this enzyme to be effective and superior to hydroquinone in skin whitening. In a non-controlled study, this enzyme was applied to

neg: Manganese peroxidase Manganese peroxidase In enzymology, a manganese peroxidase () is an enzyme that catalyzes the chemical reaction The 3 substrates of this enzyme are Mn(II), H, and HO, whereas its two products are Mn(III) and HO. This enzyme belongs to the family of oxidoreductases, to be specific those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is Mn(II):hydrogen-peroxide oxidoreductase. Other names in common use include peroxidase-M2, and Mn-dependent (NADH-oxidizing) peroxidase. It employs one cofactor, heme. This enzyme needs Ca for activity. White rot fungi secrete this enzyme to aid lignin degradation. Manganese peroxidase (commonly referred

neg: Catalysis the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available. This reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms. Upon the addition of a small amount of manganese dioxide, the hydrogen peroxide reacts rapidly. This effect is readily seen by the effervescence of oxygen. The manganese dioxide is not consumed in the reaction, and thus may be recovered unchanged, and re-used indefinitely. Accordingly, manganese dioxide "catalyses"

neg: Baeyer–Villiger oxidation Therefore, the reactivity trend shows TFPAA > 4-nitroperbenzoic acid > mCPBA and performic acid > peracetic acid > hydrogen peroxide > tert-butyl hydroperoxide. The peroxides are much less reactive than the peroxyacids. The use of hydrogen peroxide even requires a catalyst. In addition, using organic peroxides and hydrogen peroxide tends to generate more side-reactivity due to their promiscuity. The use of peroxyacids and peroxides when performing the Baeyer–Villiger oxidation can cause the undesirable oxidation of other functional groups. Alkenes and amines are a few of the groups that can be oxidized. For instance, alkenes in the substrate, particularly when electron-rich,

neg: Hydrogen peroxide - urea Hydrogen peroxide - urea Hydrogen peroxide - urea (also called Hyperol, artizone, urea hydrogen peroxide, and UHP) is a solid composed of equal amounts of hydrogen peroxide and urea. This compound is a white crystalline solid which dissolves in water to give free hydrogen peroxide. Often called carbamide peroxide in the dental office, it is used as a source of hydrogen peroxide for bleaching, disinfection, and oxidation. Hydrogen peroxide - urea contains solid and water-free hydrogen peroxide, which offers a higher stability and better controllability than liquid hydrogen peroxide when used as an oxidizing agent. For the preparation of the

neg: Nicotinamide adenine dinucleotide a hydride from the other substrate. Depending on the enzyme, the hydride donor is positioned either "above" or "below" the plane of the planar C4 carbon, as defined in the figure. Class A oxidoreductases transfer the atom from above; class B enzymes transfer it from below. Since the C4 carbon that accepts the hydrogen is prochiral, this can be exploited in enzyme kinetics to give information about the enzyme's mechanism. This is done by mixing an enzyme with a substrate that has deuterium atoms substituted for the hydrogens, so the enzyme will reduce NAD by transferring deuterium rather than hydrogen.

neg: Galactose oxidase the corresponding aldehyde and hydrogen peroxide. It has been shown that galactose oxidase is also able to catalyze various primary alcohols other than galactose. In fact, galactose oxidase catalyzes dihydroxyacetone three times faster than it does to galactose. The reaction is regioselective, in that it cannot oxidize secondary alcohol. This two-electron oxidation is achieved by the double-redox site: the copper(II) metal center and the free radical, each capable of accepting one electron from the substrate. This double-redox center has three accessible oxidation levels. In the catalytic cycle of galactose oxidase, the enzyme shuttles between the fully oxidized form and the

neg: Lactoperoxidase the enzyme glucose oxidase () that also takes place in saliva. Glucose, in turn, can be formed from starch in the presence of the saliva enzyme amyloglucosidase (). These relatively short lived oxidized intermediates have potent bactericidal effects, hence lactoperoxidase is part of the antimicrobial defense system in tissues that express lactoperoxidase. The lactoperoxidase system is effective in killing a range of aerobic and certain anaerobic microorganisms. Research (1984): "The effect of lactoperoxidase-thiocyanate-hydrogen peroxide mixtures on bacteria is dependent on experimental conditions. If the bacteria are cultured after the exposure to lactoperoxidase-thiocyanate-hydrogen peroxide on nutrient agar under aerobic conditions, they

neg: Antioxidant "S"-transferases. This system is found in animals, plants and microorganisms. Glutathione peroxidase is an enzyme containing four selenium-cofactors that catalyzes the breakdown of hydrogen peroxide and organic hydroperoxides. There are at least four different glutathione peroxidase isozymes in animals. Glutathione peroxidase 1 is the most abundant and is a very efficient scavenger of hydrogen peroxide, while glutathione peroxidase 4 is most active with lipid hydroperoxides. Surprisingly, glutathione peroxidase 1 is dispensable, as mice lacking this enzyme have normal lifespans, but they are hypersensitive to induced oxidative stress. In addition, the glutathione "S"-transferases show high activity with lipid peroxides. These enzymes

neg: Reverse phase protein lysate microarray streptavidin-biotin-peroxidase complex followed by biotinyl-tyramide/hydrogen peroxide and streptavidin-peroxidase. Development is completed using hydrogen peroxide and scans of the slides are obtained (1). Tyramide signal amplification works as follows: immobilized horseradish peroxidase (HRP) converts tyramide into reactive intermediate in the presence of hydrogen peroxide. Activated tyramide binds to neighboring proteins close to a site where the activating HRP enzyme is bound. This leads to more tyramide molecule deposition at the site; hence the signal amplification. Lance Liotta and Emanual Petricoin invented the RPMA technique in 2001 (see history section below), and have developed a multiplexed detection method using near-infrared fluorescent techniques.

neg: Glucose glucose. In concentrated solutions of glucose with a low proportion of other carbohydrates, its concentration can be determined with a polarimeter. For sugar mixtures, the concentration can be determined with a refractometer, for example in the Oechsle determination in the course of the production of wine. The enzyme glucose oxidase (GOx) converts glucose into gluconic acid and hydrogen peroxide while consuming oxygen. Another enzyme, peroxidase, catalyzes a chromogenic reaction (Trinder reaction) of phenol with 4-aminoantipyrine to a purple dye. The test strip method employs the above-mentioned enzymatic conversion of glucose to gluconic acid to form hydrogen peroxide. The reagents are

neg: Oxidative enzyme or denatures the enzyme) or by preventing oxygen from getting to the surface (such as by covering the fruit). Oxidative enzyme An oxidative enzyme is an enzyme that catalyses an oxidation reaction. Two most common types of oxidative enzymes are peroxidases, which use hydrogen peroxide, and oxidases, which use molecular oxygen. They increase the rate at which ATP is produced aerobically. Oxidative enzymes are responsible for the browning of fruits like apples. When the surface of apples are exposed to the oxygen in the air, the oxidative enzymes like polyphenol oxidase and catechol oxidase oxidize the fruit (electrons are lost

neg: 3,3'-Diaminobenzidine oxidized by hydrogen peroxide in the presence of hemoglobin to give a dark-brown color. This color change is used to detect fingerprints in blood. The solubility of DAB in water allows for adaptability compared to other detection solutions which use toxic solvents. Improperly prepared tissue samples may give false positives. In research, this reaction is used to stain cells that were prepared with hydrogen peroxidase enzyme, following common immunocytochemistry protocols. Relevant to Alzheimer's disease, Aβ protein amyloid plaques are targeted by a primary antibody, and subsequently by a secondary antibody, which is conjugated with a peroxidase enzyme. This will bind

neg: Oxidative enzyme Oxidative enzyme An oxidative enzyme is an enzyme that catalyses an oxidation reaction. Two most common types of oxidative enzymes are peroxidases, which use hydrogen peroxide, and oxidases, which use molecular oxygen. They increase the rate at which ATP is produced aerobically. Oxidative enzymes are responsible for the browning of fruits like apples. When the surface of apples are exposed to the oxygen in the air, the oxidative enzymes like polyphenol oxidase and catechol oxidase oxidize the fruit (electrons are lost to the air). Such browning can be prevented by cooking the fruit or lowering the pH (which destroys, inactivates,

neg: Hydrogen peroxide contact solutions period of time or overnight then replaced it with a neutralizing saline. These systems used a catalyse enzyme in saline form and was preserved. The AOsept system made by American Optical was the peroxide solution uses a disk to neutralize the solution. The Lensept system was also similar and used two different cups, one contained the disc and the other was for soaking!Oxysept and Omnicare was slightly different from the other two brands in that it uses tablets for the neutralization effect, which causes a slower process. The result of the tablets is a longer exposure to more concentrated hydrogen

neg: Cytochrome c peroxidase Cytochrome c peroxidase Cytochrome "c" peroxidase, or CCP, is a water-soluble heme-containing enzyme of the peroxidase family that takes reducing equivalents from cytochrome "c" and reduces hydrogen peroxide to water: CCP can be derived from aerobically grown yeast strains and can be isolated in both native and recombinant forms with high yield from "Saccharomyces cerevisae." The enzyme’s primary function is to eliminate toxic radical molecules produced by the cell which are harmful to biological systems. It works to maintain low concentration levels of hydrogen peroxide, which is generated by the organism naturally through incomplete oxygen reduction. When glucose levels in

neg: Galactose oxidase "Fusarium graminearum" NRRL 2903 (formerly misidentified as "Dactylium dendroides"), and other species of Fusarium and Aspergillus genera, galactose oxidase is first isolated in 1959. This enzyme is secreted by fungi to function in extracellular space. Although the oxidation reaction of D-galactose gives galactose oxidase its name, the coupled reduction of dioxygen to hydrogen peroxide is believed to have greater physiological significance in yeasts. Hydrogen peroxide which can be produced by yeasts in this way is possibly a bacteriostatic agent. Galactose oxidase contains 639 amino acids. It is a single peptide monomer that has three β-structural domains. Domain 1 (residues 1-155)

neg: Mandelonitrile lyase solved for this class of enzymes, with the PDB accession code . Mandelonitrile lyase In enzymology, a mandelonitrile lyase (, "(R)-HNL", "(R)-oxynitrilase", "(R)-hydroxynitrile lyase") is an enzyme that catalyzes the chemical reaction Hence, this enzyme has one substrate, mandelonitrile, and two products, hydrogen cyanide and benzaldehyde. This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is mandelonitrile benzaldehyde-lyase (hydrogen cyanide-forming). Other names in common use include hydroxynitrile lyase, (R)-oxynitrilase, oxynitrilase, D-oxynitrilase, D-alpha-hydroxynitrile lyase, and mandelonitrile benzaldehyde-lyase. This enzyme participates in cyanoamino acid metabolism. It has 2 cofactors:

neg: Hydrogen peroxide contact solutions peroxide. Following recommendations to add an enzymatic cleaner weekly, increases costs. Hydrogen peroxide contact solutions Hydrogen peroxide contact solutions are storage solutions for contact lenses that rely on hydrogen peroxide to clean the contacts and break up proteins and deposits during the disinfection process. The majority of hydrogen peroxide solutions are 3% hydrogen peroxide. This enables the solution to break down any proteins that coat the contacts after a long period of use. Hydrogen peroxide is always used alongside a neutralizing product. The intention is to prevent the hydrogen peroxide from contact with the eye, which could damage the corneal

neg: Clinistrip Clinistrip Clinistrip, also known as CLINISTIX or the brand name Diastix, are specific clinical sticks for the detection of glucose. Clinistrip consists of a section that contains glucose oxidase that has been dried onto the paper pad. It is an example of a biosensor-based test for glucose. This is similar to the glucose oxidase assay, as the glucose in the urine, once the stick has been dipped into the urine, is oxidized to yield gluconic acid and hydrogen peroxide. The enzyme peroxidase is also present on the pad, and it utilizes the hydrogen peroxide produced to oxidise a dye that

neg: Hydrogen peroxide contact solutions Hydrogen peroxide contact solutions Hydrogen peroxide contact solutions are storage solutions for contact lenses that rely on hydrogen peroxide to clean the contacts and break up proteins and deposits during the disinfection process. The majority of hydrogen peroxide solutions are 3% hydrogen peroxide. This enables the solution to break down any proteins that coat the contacts after a long period of use. Hydrogen peroxide is always used alongside a neutralizing product. The intention is to prevent the hydrogen peroxide from contact with the eye, which could damage the corneal cells in the epithelium. While this would not result in permanent

neg: Arginase as the tetrahedral intermediate is formed. Arginase's active site is extraordinarily specific. Modifying the substrate structure and/or stereochemistry severely lowers the kinetic activity of the enzyme. This specificity occurs due to the high number of hydrogen bonds between substrate and enzyme; direct or water-facilitated hydrogen bonds exist, saturating both the four acceptor positions on the alpha carboxylate group and all three positions on the alpha amino group. N-hydroxy-L-arginine (NOHA), an intermediate of NO biosynthesis, is a moderate inhibitor of arginase. Crystal structure of its complex with the enzyme reveals that it displaces the metal-bridging hydroxide ion and bridges the binuclear

neg: Biosensor which oxidises glucose producing hydrogen peroxide which is detected by the electrode. To overcome the limitation of amperometric sensors, a flurry of research is present into novel sensing methods, such as fluorescent glucose biosensors. The interferometric reflectance imaging sensor (IRIS) is based on the principles of optical interference and consists of a silicon-silicon oxide substrate, standard optics, and low-powered coherent LEDs. When light is illuminated through a low magnification objective onto the layered silicon-silicon oxide substrate, an interferometric signature is produced. As biomass, which has a similar index of refraction as silicon oxide, accumulates on the substrate surface, a change

neg: Active site and the active site is so important that in some cases the enzyme can still function properly even though all other parts are mutated and lose function. Initially, the reaction between the active site and the substrate is non-covalent and temporal. There are four important kinds of interaction that hold the substrate in a right orientation and form an enzyme-substrate complex(ES complex): hydrogen bond, Van der Waals force, hydrophobic interaction and electrostatic force. The charges distribution on the substrate and active site must be complementary, which means all positive and negative charges must be cancelled out. Otherwise, there will be

neg: Mandelonitrile lyase Mandelonitrile lyase In enzymology, a mandelonitrile lyase (, "(R)-HNL", "(R)-oxynitrilase", "(R)-hydroxynitrile lyase") is an enzyme that catalyzes the chemical reaction Hence, this enzyme has one substrate, mandelonitrile, and two products, hydrogen cyanide and benzaldehyde. This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is mandelonitrile benzaldehyde-lyase (hydrogen cyanide-forming). Other names in common use include hydroxynitrile lyase, (R)-oxynitrilase, oxynitrilase, D-oxynitrilase, D-alpha-hydroxynitrile lyase, and mandelonitrile benzaldehyde-lyase. This enzyme participates in cyanoamino acid metabolism. It has 2 cofactors: flavin, and flavoprotein. As of late 2007, only one structure has been

neg: Selenium in biology acid selenocysteine. Twenty-five selenoproteins are encoded in the human genome. The glutathione peroxidase family of enzymes (abbreviated GSH-Px) catalyze reduction of hydrogen peroxide and organic hydroperoxides: The two H atoms are donated by thiols in a process that begins with oxidation of a selenol side chain in GSH-Px. The organoselenium compound ebselen is a drug used to supplement the action of GSH-Px. It functions as a catalyst for the destruction of hydrogen peroxide. A related selenium-containing enzyme in some plants and in animals (thioredoxin reductase) generates reduced thioredoxin, a dithiol that serves as an electron source for peroxidases and also

neg: Arsenic biochemistry reactive oxygen species (ROS), and reactive nitrogen species (RNS). Reactive oxygen species are produced by the enzyme NADPH oxidase, which transfers electrons from NADPH to oxygen, synthesizing a superoxide, which is a reactive free radical. This superoxide can react to form hydrogen peroxide and a reactive oxygen species. The enzyme NADPH oxidase is able to generate more reactive oxygen species in the presence of arsenic, due to the subunit p22phax, which is responsible for the electron transfer, being upregulated by arsenic. The reactive oxygen species are capable of stressing the endoplasmic reticulum, which increases the amount of the unfolded protein

neg: Hydrogen peroxide in fraudulent treatment claims. The amount of hydrogen peroxide in biological systems can be assayed using a fluorometric assay. About 60% of the world's production of hydrogen peroxide is used for pulp- and paper-bleaching. The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. Sodium percarbonate, which is an adduct of sodium carbonate and hydrogen peroxide, is the active ingredient in such products as OxiClean and Tide laundry detergent. When dissolved in water, it releases hydrogen peroxide and sodium carbonate: <chem> Na2CO3*3 H2O2 -> 2Na2CO3 + 3

neg: Iron oxide in the enzyme within the plane of the membrane. The second electron pushes the first electron to the second heme group so that it can associate with the first heme group. For the transfer to occur, the second heme must be bound to extracellular oxygen which is the acceptor of the electron. This enzyme can also be located within the membranes of intracellular organelles allowing the formation of to occur within organelles. The formation of hydrogen peroxide () can occur spontaneously when the environment has a lower pH especially at pH 7.4. The enzyme superoxide dismutase can also catalyze this

neg: Horseradish peroxidase Horseradish peroxidase 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. The structure of the enzyme was first solved by X-ray crystallography in 1997 and has since been solved several times with various substrates. It is an largely alpha-helical protein which binds heme as a redox cofactor. Alone, the HRP enzyme, or conjugates thereof, is of little value; its presence must be made visible using a

neg: Antioxidant interacting network of antioxidant enzymes. Here, the superoxide released by processes such as oxidative phosphorylation is first converted to hydrogen peroxide and then further reduced to give water. This detoxification pathway is the result of multiple enzymes, with superoxide dismutases catalysing the first step and then catalases and various peroxidases removing hydrogen peroxide. As with antioxidant metabolites, the contributions of these enzymes to antioxidant defenses can be hard to separate from one another, but the generation of transgenic mice lacking just one antioxidant enzyme can be informative. Superoxide dismutases (SODs) are a class of closely related enzymes that catalyze the

neg: Adenosine deaminase bond with Asp19, while the 5'-OH forms a hydrogen bond with His17. Two further hydrogen bonds are formed to water molecules, at the opening of the active site, by the 2'-OH and 3'-OH of the substrate. Due to the recessing of the active site inside the enzyme, the substrate, once bound, is almost completely sequestered from solvent. The surface exposure of the substrate to solvent when bound is 0.5% the surface exposure of the substrate in the free state. ADA irreversibly deaminates adenosine, converting it to the related nucleoside inosine by the substitution of the amino group for a keto

neg: Hydrogen peroxide H2O2</chem> By themselves these bleaching agents are only effective at wash temperatures of or above and so are often used in conjunction with bleach activators, which facilitate cleaning at lower temperatures. It is used in the production of various organic peroxides with dibenzoyl peroxide being a high volume example. It is used in polymerisations, as a flour bleaching agent and as a treatment for acne. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid are also produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide. Hydrogen peroxide is used in certain

neg: Flavin reductase hydrophobic core in flavin reductase The enzyme has two binding sites, one for NADPH and one for the flavin mononucleotide substrate. The isoalloxazine ring of flavin mononucleotide is where reduction occurs. Therefore, this is where flavin creates a variety of hydrogen bonds to connect to the amino acid side chains of flavin reductase. Side chains 167–169 in FRP block the isoalloxazine ring in FAD from binding the enzyme, making FRP an FMN specific flavin reductase. The placement of methyl groups in the isoalloxazine ring can also have an effect on the binding and specificity of the enzyme for substrate. There

neg: Di-haem cytochrome c peroxidase Di-haem cytochrome c peroxidase In molecular biology, the di-haem cytochrome c peroxidase family is a group of distinct cytochrome c peroxidases (CCPs) that contain two haem groups. Similar to other cytochrome c peroxidases, they reduce hydrogen peroxide to water using c-type haem as an oxidizable substrate. However, since they possess two, instead of one, haem prosthetic groups, this family of bacterial CCPs reduce hydrogen peroxide without the need to generate semi-stable free radicals. The two haem groups have significantly different redox potentials. The high potential (+320 mV) haem feeds electrons from electron shuttle proteins to the low potential (-330 mV)

neg: Protein disulfide-isomerase and PrxIV (peroxiredoxin IV). Ero1 is thought to be the main reoxidizing protein of PDI, and the pathway of reoxidation of PDI for Ero1 is more understood than that of other proteins. Ero1 accepts electrons from PDI and donates these electrons to oxygen molecules in the ER, which leads to the formation of hydrogen peroxide. The reduced (dithiol) form of protein disulfide-isomerase is able to catalyze a reduction of a misformed disulfide bridge of a substrate through either reductase activity or isomerase activity. For the reductase method, a misfolded substrate disulfide bond is converted to a pair of reduced cysteine

neg: Kastle–Meyer test as an external source of electrons. In its reaction with hydrogen peroxide, the heme center of hemoglobin behaves as a peroxidase, reducing the peroxide to water. This activity depletes hemoglobin of electrons that are, in turn, re-supplied by the phenolphthalin. Donating electrons to hemoglobin converts the phenolphthalin back into the intensely colored phenolphthalein. As long as the enzyme survives, the reaction of heme with peroxide is catalytic, making this test very sensitive to small quantities of blood present on the test swab. The hemoglobin-catalyzed reduction of peroxide that occurs is shown in the reaction below. The two electrons are supplied

neg: Hydrogen peroxide peroxide acting as an oxidizing agent): and sulfite () is oxidized to sulfate (). However, potassium permanganate is reduced to by acidic . Under alkaline conditions, however, some of these reactions reverse; for example, is oxidized to (as ). In basic solution, hydrogen peroxide can reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen gas is also produced. For example, hydrogen peroxide will reduce sodium hypochlorite and potassium permanganate, which is a convenient method for preparing oxygen in the laboratory: Hydrogen peroxide is frequently used as an oxidizing agent. Illustrative is oxidation of thioethers to

neg: Sterilization (microbiology) in this case, it is prepared on-site by depolymerization of solid paraformaldehyde. Many vaccines, such as the original Salk polio vaccine, are sterilized with formaldehyde. Hydrogen peroxide, in both liquid and as vaporized hydrogen peroxide (VHP), is another chemical sterilizing agent. Hydrogen peroxide is a strong oxidant, which allows it to destroy a wide range of pathogens. Hydrogen peroxide is used to sterilize heat- or temperature-sensitive articles, such as rigid endoscopes. In medical sterilization, hydrogen peroxide is used at higher concentrations, ranging from around 35% up to 90%. The biggest advantage of hydrogen peroxide as a sterilant is the short

neg: Hydrogen peroxide - urea of crystallization, hydrogen peroxide cocrystallizes with urea with the stoichiometry of 1:1. The compound is simply produced (on a scale of several hundred tonnes a year) by the dissolution of urea in excess concentrated hydrogen peroxide solution, followed by crystallization. The laboratory synthesis is analogous. Hydrogen peroxide-urea is a readily water-soluble, odorless, crystalline solid, which is available as white powder or colorless needles or platelets. Upon dissolving in various solvents, the 1:1 complex dissociates back to urea and hydrogen peroxide. So just like hydrogen peroxide, the (erroneously) so-called adduct is an oxidizer but the release at room temperature in the

neg: Stearoyl-CoA desaturase-1 the substrate tail at the location where the di-iron catalytic centre introduces the double bond. The literature suggests that the enzyme accomplishes the desaturation reaction by removing the first hydrogen at C9 position and then the second hydrogen from the C-10 position. Because the C-9 and C-10 are positioned close to the iron-containing center of the enzyme, this mechanism is hypothesized to be specific for the position at which the double bond is formed. Monounsaturated fatty acids, the products of SCD-1 catalyzed reactions, can serve as substrates for the synthesis of various kinds of lipids, including phospholipids, triglycerides, and can

neg: Hydrogen peroxide contact solutions solution. At this point, it is safe to use the contacts. After extended use, the platinum coated disk must be replaced. Both hydrogen peroxide and multipurpose solutions remove debris and build-up. Significant differences exist between the two. Hydrogen peroxide has the ability to penetrate microbial films, which helps create a deeper clean. Hydrogen peroxide solutions do not contain preservatives. This can be beneficial for people who are allergic or sensitive to the preservatives in multipurpose solutions. Hydrogen peroxide solutions have a greater ability to fight acanthamoeba keratitis, an infection that can cause blindness. Some researchers have found the peroxide cleaning

neg: High-test peroxide mass of high-concentration hydrogen peroxide at ambient pressure will produce vapor-phase hydrogen peroxide, which can detonate. This hazard is mitigated, but not entirely eliminated, with vacuum distillation. Other approaches for concentrating hydrogen peroxide are sparging and fractional crystallization. High-concentration hydrogen peroxide was formerly available in 70, 90, and 98% concentrations in sizes of 1-gallon, 30-gallon, and bulk-tanker truck volumes. Hydrogen peroxide in concentrations of at least 35% appear on the US Department of Homeland Security’s Chemicals of Interest list. Since many common substances catalyze peroxide’s exothermic decomposition into steam and oxygen, handling of HTP requires special care and equipment. It

neg: Oxalate degrading enzyme Oxalate degrading enzyme An oxalate degrading enzyme is a type of enzyme that catalyzes the biodegradation of oxalate. Enzymes in this class include oxalate oxidase, oxalate decarboxylase, oxalyl-CoA decarboxylase, and formyl-CoA transferase. Oxalate oxidase （Enzyme Commission number ）occurs mainly in plants. It can degrade oxalic acid into carbon dioxide and hydrogen peroxide. Oxalate decarboxylase (OXDC，) is a kind of oxalate degrading enzyme containing Mn2+, found mainly in fungi or some bacteria. Brown rot fungi secrete oxalate to break down cellulose fibers of wood, but deploy this enzyme to permit regulatory control over the total quantity of oxalate present. It can

neg: Tooth whitening the risk of chemical burns to the soft tissues. The bleaching agent is either carbamide peroxide, which breaks down in the mouth to form hydrogen peroxide, or hydrogen peroxide itself. The bleaching gel typically contains between 10% and 44% carbamide peroxide, which is roughly equivalent to a 3% to 16% hydrogen peroxide concentration. The legal percentage of hydrogen peroxide allowed to be given is 0.1-6%. Bleaching agents are only allowed to be given via dental practitioners, dental therapists and dental hygienists. Bleaching is least effective when the original tooth color is grayish and may require custom bleaching trays. Bleaching is

neg: Hydrogen peroxide of Governmental Industrial Hygienists (ACGIH) as a "known animal carcinogen, with unknown relevance on humans". For workplaces where there is a risk of exposure to the hazardous concentrations of the vapours, continuous monitors for hydrogen peroxide should be used. Information on the hazards of hydrogen peroxide is available from OSHA and from the ATSDR. Notes Bibliography Hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a pale blue, clear liquid, slightly more viscous than water. Hydrogen peroxide is the simplest peroxide (a compound with an oxygen–oxygen single bond). It is used

neg: Phosphodiesterase 2 methyl group on Bay 60-7550, which replaces the nitrogen atom in PDP decreasing the possibility to form hydrogen bonds with the enzyme in an important site for substrate and inhibitor binding. The oxindole structure differs from the other inhibitors since it is more divergent from the purine ring system and has less hydrogen binding possibilities. The molecule also lacks the large side group, analogous to the dimethoxybenzyl group of Bay 60-7550 and PDP. It is difficult to predict possible interactions to the enzyme without a co-crystal structure of the phenomenon. There is a lack of co-crystal structures of inhibitors bound

neg: Horseradish peroxidase HRP-like artificial enzymes have been used for lots of applications, ranging from biomarker detection and tumor immunostaining to antibiofouling. Horseradish peroxidase 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. The structure of the enzyme was first solved by X-ray crystallography in 1997 and has since been solved several times with various substrates. It is an largely alpha-helical protein which binds heme as a redox cofactor.

neg: Lactoylglutathione lyase respectively. In both the hemithioacetal substrate and the (R)-S-lactoylglutathione product, the glutathione moiety is bonded to the C carbonyl group. The basic mechanism of glyoxalase I is as follows. The substrate hemithioacetal is formed when a molecule of glutathione — probably in its reactive thiolate form — attacks the C carbonyl of methylglyoxal or a related compound, rendering that carbon tetravalent. This reaction occurs spontaneously in the cell, without the involvement of the enzyme. This hemithioacetal is then bound by the enzyme, which shifts a hydrogen from C to C. The C carbonyl is reduced to a tetravalent alcohol form

neg: Hydrogen peroxide its name to the phrase "peroxide blonde". Hydrogen peroxide is also used for tooth whitening. It can be found in most whitening toothpastes. Hydrogen peroxide has shown positive results involving teeth lightness and chroma shade parameters. It works by oxidizing colored pigments onto the enamel where the shade of the tooth can indeed become lighter. Hydrogen peroxide can be mixed with baking soda and salt to make a home-made toothpaste. Hydrogen peroxide may be used to treat acne, although benzoyl peroxide is a more common treatment. Practitioners of alternative medicine have advocated the use of hydrogen peroxide for various conditions,

neg: Oxidase Oxidase An oxidase is an enzyme that catalyzes an oxidation-reduction reaction, especially one involving dioxygen (O) as the electron acceptor. In reactions involving donation of a hydrogen atom, oxygen is reduced to water (HO) or hydrogen peroxide (HO). Some oxidation reactions, such as those involving monoamine oxidase or xanthine oxidase, typically do not involve free molecular oxygen. The oxidases are a subclass of the oxidoreductases. An important example is cytochrome c oxidase, the key enzyme that allows the body to employ oxygen in the generation of energy and the final component of the electron transfer chain. Other examples are: In

neg: Anthraquinone process Anthraquinone process The anthraquinone process is a process for the production of hydrogen peroxide, which was developed by BASF. The industrial production of hydrogen peroxide is based on the reduction of oxygen, as in the direct synthesis from the elements. Instead of hydrogen itself, however, a 2-alkyl-anthrahydroquinone, which is generated before from the corresponding 2-alkyl-anthraquinone by catalytic hydrogenation with palladium. Oxygen and the organic phase react under formation of the anthraquinone and hydrogen peroxide. Among other alkyl groups (R) ethyl- and tert. Butyl are used, e.g., 2-ethylanthraquinone. The hydrogen peroxide is then extracted with water and in a second step

neg: Hydrogen peroxide oxygen within the body. This makes it similar to other oxygen-based therapies, such as ozone therapy and hyperbaric oxygen therapy. Both the effectiveness and safety of hydrogen peroxide therapy is scientifically questionable. Hydrogen peroxide is produced by the immune system but in a carefully controlled manner. Cells called phagocytes engulf pathogens and then use hydrogen peroxide to destroy them. The peroxide is toxic to both the cell and the pathogen and so is kept within a special compartment, called a phagosome. Free hydrogen peroxide will damage any tissue it encounters via oxidative stress; a process which also has been proposed

neg: Neutrophil formation of a phagosome into which reactive oxygen species and hydrolytic enzymes are secreted. The consumption of oxygen during the generation of reactive oxygen species has been termed the "respiratory burst", although unrelated to respiration or energy production. The respiratory burst involves the activation of the enzyme NADPH oxidase, which produces large quantities of superoxide, a reactive oxygen species. Superoxide decays spontaneously or is broken down via enzymes known as superoxide dismutases (Cu/ZnSOD and MnSOD), to hydrogen peroxide, which is then converted to hypochlorous acid (HClO), by the green heme enzyme myeloperoxidase. It is thought that the bactericidal properties of