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  • oxidase
  • Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase (also known as catecholase, or catechol oxidase). (wikipedia.org)
  • Catechol oxidase is a copper oxidase that contains a type 3 di-copper cofactor and catalyzes the oxidation of ortho-diphenols into ortho-quinones coupled with the reduction of molecular oxygen to water. (wikipedia.org)
  • In plants, catechol oxidase plays a key role in enzymatic browning by catalyzing the oxidation of catechol to o-quinone in the presence of oxygen, which can rapidly polymerize to form the melanin that grants damaged fruits their dark brown coloration. (wikipedia.org)
  • Polyphenol oxidases are a family of di-copper metalloenzymes that include tyrosinase and catechol oxidase. (wikipedia.org)
  • The key difference between the two related enzymes is that tyrosinase can catalyze the hydroxylation of monophenols to diphenols (monophenolase activity) as well as the oxidation of the o-diphenol to the o-quinone (diphenolase activity) whereas catechol oxidase only possesses diphenolase activity. (wikipedia.org)
  • When plant tissue is damaged, the chloroplast may rupture and release catechol oxidase into the plant cytoplasm, and vacuoles may also rupture, releasing stored catechol into the cytoplasm. (wikipedia.org)
  • Thus, tissue damage facilitates the interaction of catechol oxidase with its substrate to produce o-benzoquinone, which can polymerize non-enzymatically to yield melanins that form an insoluble barrier for wound protection. (wikipedia.org)
  • Catechol oxidase is nuclear-encoded, and its N-terminal end contains a signal peptide that directs the protein to the chloroplast thylakoid lumen, where it can either be soluble or loosely associated with the thylakoid membrane. (wikipedia.org)
  • Initially transcribed as a pro-enzyme, the catechol oxidase precursor undergoes two rounds of proteolytic processing and transport before it enters the thylakoid lumen. (wikipedia.org)
  • Based on analysis of the precursor and mature catechol oxidase purified from Ipomoea batatas, proteolytic processing removes both the N-terminal transit peptide as well as a C-terminal domain that covers the enzyme active site. (wikipedia.org)
  • The crystal structure of catechol oxidase purified from Ipomoea batatas has been resolved in its active form in both the oxidized Cu(II)-Cu(II) state and the reduced Cu(I)-Cu(I) state. (wikipedia.org)
  • While the active site of both tyrosinase and catechol oxidase contain the di-copper center, variations in each enzyme's respective structure result in differing activity. (wikipedia.org)
  • In catechol oxidase, a phenylalanine side-chain (Phe261) is above one of the copper centers and prevents the substrate from coordinating with both copper ions in the active site. (wikipedia.org)
  • This precludes the bidentate coordination complex necessary for di-phenolate hydroxylation characteristic of tyrosinase but absent in catechol oxidase. (wikipedia.org)
  • Although a crystal structure of catechol oxidase has been solved, questions concerning the exact mechanism of the reaction remain. (wikipedia.org)
  • Enzyme nomenclature differentiates between monophenol oxidase enzymes (tyrosinases) and o-diphenol:oxygen oxidoreductase enzymes (catechol oxidases). (wikipedia.org)
  • A mixture of monophenol oxidase and catechol oxidase enzymes is present in nearly all plant tissues, and can also be found in bacteria, animals, and fungi. (wikipedia.org)
  • COMT
  • Since the identification of Catechol-O-Methyltransferase (COMT) by Axelrod in 1957, many inhibitors of this enzyme have been reported. (eurekaselect.com)
  • This review summarizes the major classes of COMT inhibitors, from early catechol and pyrogallol variants to bisubstrate inhibitors. (eurekaselect.com)
  • Using catechol O-methyltransferase (COMT) as a model, we perform discrete molecular dynamics and computational docking simulations to elucidate the initial stages of cofactor binding. (nih.gov)
  • A novel isolation procedure was developed that allowed the purification of rat liver and human placenta catechol-O-methyltransferase (EC 2.1.1.6, COMT) enzyme from rat and human sources to a degree sufficient to allow the amino acid sequencing of the enzyme. (lu.se)
  • misc{d359f84f-dce1-45b6-b22f-f3eac7b75b3d, abstract = {A novel isolation procedure was developed that allowed the purification of rat liver and human placenta catechol-O-methyltransferase (EC 2.1.1.6, COMT) enzyme from rat and human sources to a degree sufficient to allow the amino acid sequencing of the enzyme. (lu.se)
  • The catechol estrogens are formed from estradiol and estrone by cytochrome P450 enzymes predominantly in the liver but also in extrahepatic tissues, and are metabolized by catechol O-methyltransferase (COMT) into methoxylated estrogens such as 2-methoxyestradiol and 4-methoxyestrone as well as by conjugation via other phase II enzymes. (wikipedia.org)
  • In addition to being substrates for COMT similarly to catecholamines like dopamine, norepinephrine, and epinephrine, catechol estrogens are potent competitive inhibitors of COMT as well as of tyrosine hydroxylase, and may affect both catecholamine biosynthesis and metabolism. (wikipedia.org)
  • In humans, catechol-O-methyltransferase protein is encoded by the COMT gene. (wikipedia.org)
  • Any compound having a catechol structure, like catecholestrogens and catechol-containing flavonoids, are substrates of COMT. (wikipedia.org)
  • Catechol-O-methyl transferase (COMT). (wikipedia.org)
  • substrate
  • PO activity was determined in a 96-well microplate in a total reaction volume of 300 [micro]L per well with catechol as the substrate, according to the method described by Benjamin & Montgomery (1913). (thefreedictionary.com)
  • Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut and left out), the colorless catechol oxidizes to reddish-brown melanoid pigments, derivatives of benzoquinone. (wikipedia.org)
  • resorcinol
  • Commonly, the molecular structure of flavonoids of high biological activity like quercetin or naringenin includes a group derived from resorcinol and/or catechol [5, (scielo.org.ar)
  • quinones
  • 9 Once exposed to oxygen, catechol residues are oxidized to reactive o -quinones. (rsc.org)
  • Cyclic esters are formed upon treatment with phosphorus trichloride and phosphorus oxychloride, carbonyl chloride, and sulphuryl chloride: C6H4(OH)2 + XCl2 → C6H4(O2X) + 2 HCl where X = CO, SO2, PCl, P(O)Cl Catechols produce quinones with the addition of ceric ammonium nitrate (CAN). (wikipedia.org)
  • hydroxyl
  • 1,2-CTD uses Fe3+ as a cofactor to cleave the carbon-carbon bond between the phenolic hydroxyl groups of catechol, thus yielding muconic acid as its product. (wikipedia.org)
  • In contrast, 2,3-CTD utilizes Fe2+ as a cofactor to cleave the carbon-carbon bond adjacent to the phenolic hydroxyl groups of catechol, thus yielding 2-hydroxymuconaldehye as its product. (wikipedia.org)
  • The second catechol hydroxyl group on carbon 3 (C3) is coordinated to Fe3+ after its deprotonation by the Tyr200 ligand. (wikipedia.org)
  • mechanism
  • It can safely be presumed that a part of the rearrangement proceeds counter-clockwise by the ortho mechanism as for catechol monoallyl ether, thereby yielding the expected 3-allylcatechol ( VIII ). (erowid.org)
  • Structural mechanism of S-adenosyl methionine binding to catechol O-methyltransferase. (nih.gov)
  • The results are consistent with a mechanism in which O 2 oxidizes both mono-deprotonated and fully deprotonated catechol anions. (rsc.org)
  • As a defence mechanism, siderocalin can substitute ferric bis-catechol complexes (formed under physiological conditions) with a third catechol, in order to achieve a hexacoordinate ferric complex, resulting in higher affinity binding. (wikipedia.org)
  • catechin
  • Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809 - 1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of Mimosa catechu (Acacia catechu L.f). (wikipedia.org)
  • methionine
  • A functional single-nucleotide polymorphism (a common normal variant) of the gene for catechol-O-methyltransferase results in a valine to methionine mutation at position 158 (Val158Met) rs4680. (wikipedia.org)
  • undergo
  • In reducing conditions, catechol residues can undergo various interactions, such as hydrogen bonding, electrostatic interactions or metal-catechol coordination. (rsc.org)
  • catecholamines
  • Catecholamines are biochemically significant hormones/neurotransmitters that are phenethylamines in which the phenyl group has a catechol skeleton structure. (wikipedia.org)
  • reversible
  • Reversible increases in catechol signal were observed during reversible increases in arterial partial CO2 pressure (PaCO2) from 20 to 60 mmHg after alteration of tidal volume (n = 5 intact rats, n = 5 after carotid sinus deafferentation). (biomedsearch.com)
  • A reversible increase in inspiratory CO2 combined with constant tidal volume led to changes in PaCO2 from 40 mmHg to 50 or 60 or 70 mmHg for 60 min (n = 5 in each group) and to a reversible increase in catechol signal (r = 0.76). (biomedsearch.com)
  • metabolism
  • The level of catechol metabolism in the RVLM 1) is continuously related to the level of arterial CO2, 2) functions close to its resting level under baseline nonstimulated condition with respect to CO2, and 3) is reversibly modified on changes in capnia. (biomedsearch.com)
  • Catechols such as DHSA are produced through the metabolism of cholesterol by bacteria such as Mycobacterium tuberculosis. (wikipedia.org)
  • vivo
  • A catechol signal recorded with in vivo voltammetry within the rat rostral ventrolateral medulla (RVLM) was taken as an index of the activity of RVLM adrenergic neurons and related to the level of arterial PCO2, under halothane anesthesia. (biomedsearch.com)
  • moieties
  • Catechol moieties are also found widely within the natural world. (wikipedia.org)
  • Mammalian siderophores, specifically catechols, can be found in the human gut and in siderophores, such as enterobactin, and serve as iron-binding moieties. (wikipedia.org)
  • functional
  • Catechols are found as functional groups in Nature as the 3,4-dihydroxy isomer, generally with electron donating substituents and as the 2,3-dihydroxy isomer, with an electron withdrawing substituent. (rsc.org)
  • ortho
  • However, in the case of monoallyl ether of catechol, the allyl group migrates to the para position despite the availability of an unsubstituted ortho position. (erowid.org)
  • mixture
  • 16 By exposing the catechol modified alginate to a mixture of sodium hydroxide and sodium periodate, a divalent cation-free alginate hydrogel was created that showed a high degree of viability and low immunogenicity. (rsc.org)
  • Detection
  • The amperometric results indicated that the Cu/CNFs/laccase(Lac)/Nafion/glass carbon electrode (GCE) possessed reliable analytical performance for the detection of catechol. (mdpi.com)
  • Fu J, Qiao H, Li D, Luo L, Chen K, Wei Q. Laccase Biosensor Based on Electrospun Copper/Carbon Composite Nanofibers for Catechol Detection. (mdpi.com)
  • carbon
  • Although catechol is the metabolic intermediate for both salicylate and benzoate, catechol did not induce either pathway when used as a sole carbon source. (springer.com)
  • approach
  • Here, a supramolecular approach based on ureido-pyrimidinone (UPy) modified polymers is combined with catechol chemistry in order to achieve improved cellular adhesion onto supramolecular biomaterials. (rsc.org)
  • UPy-modified hydrophobic polymers with non-cell adhesive properties are developed that can be bioactivated via a modular approach using UPy-modified catechols. (rsc.org)
  • structure
  • Urushiols are naturally existing organic compounds that have the catechol skeleton structure and diphenol functionality but with alkyl groups substituted onto the aromatic ring. (wikipedia.org)