• Ascorbate peroxidase (or L-ascorbate peroxidase, APX) (EC 1.11.1.11) is an enzyme that catalyzes the chemical reaction L-ascorbate + H2O2 ⇌ {\displaystyle \rightleftharpoons } dehydroascorbate + 2 H2O It is a member of the family of heme-containing peroxidases. (wikipedia.org)
  • APXs catalyse the H2O2-dependent oxidation of ascorbate in plants, algae and certain cyanobacteria. (wikipedia.org)
  • Hydrogen peroxide (H2O2) was added to generate the ferryl protein. (lu.se)
  • This study shows the adverse effects of irrigants such as sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2) on the adhesiveness of resin composite to tooth structures. (uwi.edu)
  • If one is intending to use 35% Food Grade Hydrogen Peroxide for oxygenation (H2O2) purposes, it is advisable that you begin with a 5-day course of 43% Pure Magnesium Peroxide Powder ( MgO2) prior to using 35% Food Grade Hydrogen Peroxide. (gaiaorganics.co.za)
  • The ascorbate-glutathione cycle (Halliwell-Asada pathway) may operate to reduce hydrogen peroxide (H2O2). (ristudypost.com)
  • It can be neutralized and the reduction of microleakage can be done by the addition of antioxidants (Sodium Ascorbate and Quercetine) to the irrigants. (uwi.edu)
  • Comparative analysis of the coronal microleakage of a self-etching priming dentin adhesive with the use of antioxidant (Sodium Ascorbate (SA) and herbal quercetin) after Sodium hypochloride (NaOCl) and hydrogen-peroxide (H 2 O 2 ) irrigation. (uwi.edu)
  • We proposed that pharmacologic ascorbate is a prodrug for preferential steady-state formation of ascorbate radical (Asc(*-)) and H(2)O(2) in the extracellular space compared with blood. (nih.gov)
  • Under physiological conditions, the immediate product of the reaction, the monodehydroascorbate radical, is reduced back to ascorbate by a monodehydroascorbate reductase (monodehydroascorbate reductase (NADH)) enzyme. (wikipedia.org)
  • H2O [3] In ascorbate peroxidase, Compound I is a transient (green) species and contains a high-valent iron species (known as ferryl heme, FeIV) and a porphyrin pi-cation radical,, as found in horseradish peroxidase. (wikipedia.org)
  • In-vitro generation of hydroxyl radical in an ascorbate/ hydrogen -peroxide system, in-vitro luminol chemiluminescence and leukotriene-B4 release by alveolar macrophages, and acute inflammatory lung injury in the rat all increased with surface complexed iron. (cdc.gov)
  • 1) Ohwada R, Ozeki Y, Saitoh Y*. High-dose ascorbic acid induces carcinostatic effects through hydrogen peroxide and superoxide anion radical generation-induced cell death and growth arrest in human tongue carcinoma cells. (pu-hiroshima.ac.jp)
  • Cancer sensitivity to free radical-inducing therapies, including ascorbate, may depend on selenium, providing a dietary approach for improving their anticancer efficacy. (princeton.edu)
  • Among enzymes, SOD is the first line of defense as it converts superoxide radical to hydrogen peroxide (H 2 O 2 ), which is later reduced to water and oxygen either by APX in ascorbate-glutathione cycle or by GPX and CAT in cytoplasm and other cellular compartments [ 12 ]. (biomedcentral.com)
  • alkoxy radical) and molecular non-radical forms (H 2 O 2 , hydrogen peroxide and 1 O 2 , singlet oxygen) 7 . (nature.com)
  • These data provide a foundation for pursuing pharmacologic ascorbate as a prooxidant therapeutic agent in cancer and infections. (nih.gov)
  • Ascorbate-dependent peroxidase activity was first reported in 1979,, more than 150 years after the first observation of peroxidase activity in horseradish plants and almost 40 years after the discovery of the closely related cytochrome c peroxidase enzyme. (wikipedia.org)
  • In contrast, AM decreased ascorbate, peroxidase activity and increased total phenolic compounds. (ac.ir)
  • Patients, the general population as a whole, and the majority of the medical community know it as "vitamin C". Whatever title is chosen to call it, I believe the biochemical effects and anticancer impact best identify "vitamin C" through its delivery of hydrogen peroxide (H202) and its function as an electron donor. (drgoodyear.com)
  • 1 ] carry out a variety of biosynthetic and degradative functions using hydrogen peroxide as the electron acceptor. (expasy.org)
  • If water stress is prolonged and/or severe, part of the energy supplied by incident photons may be redirected into processes that favor the generation of reactive oxygen species (ROS) such as hydrogen peroxide (H 2 O 2 ), leading to oxidative damage to plant tissues ( Jiang and Zhang, 2002 ). (frontiersin.org)
  • Some proteins from the APX family lack the ascorbate-binding amino acid residues suggesting that they might oxidize other molecules than ascorbate. (wikipedia.org)
  • [17] Exposure to ultraviolet (UV) radiation can cause direct photooxidation and decompose peroxides and carbonyl molecules. (wikipedia.org)
  • The bleaching mechanism is based on the decomposition of peroxides into free radicals, which react with the organic pigment molecules, transforming them into smaller and less pigmented compounds 2 . (bvsalud.org)
  • After parenteral dosing, Asc(*-) concentrations in extracellular fluid were 4- to 12-fold higher than those in blood, were as high as 250 nM, and were a function of ascorbate concentrations. (nih.gov)
  • By using the synthesized probe peroxyxanthone, H(2)O(2) in extracellular fluid was detected only after parenteral administration of ascorbate and when Asc(*-) concentrations in extracellular fluid exceeded 100 nM. (nih.gov)
  • Aim: To evaluate the effects of three hydrogen peroxide (HP) concentrations on enamel mineral content (MC), following three peroxide applications and using three methods to measure the MC. (bvsalud.org)
  • Bleaching agents designed for professional use only contain a high concentration of peroxides (30% to 40%), while the active ingredient of patient-applied (at-home) tooth bleachers, present at lower concentrations, are carbamide peroxide (10% to 20%) and hydrogen peroxide (3% to 7.5%) 3 . (bvsalud.org)
  • Such differences in the adverse effects on enamel and dentin caused by bleaching agents are due to the large number of bleaching protocols, peroxide types and concentrations, and evaluation methods. (bvsalud.org)
  • The objective of this study was to analyze the effect of different hydrogen peroxide (HP) concentrations (10%, 35% and 50%) after 1, 2 and 3 applications on an enamel surface, comparing three methodologies commonly used to evaluate the changes in the mineral contents of teeth. (bvsalud.org)
  • High-dose ascorbate (vitamin C) has shown promising anticancer activity. (princeton.edu)
  • Among them, hydrogen peroxide (H 2 O 2 ) induces polymerization of different subunits of lignin (4-hydroxy cinnamyl aldehyde, coniferyl alcohol and sinapoyl alcohol), leading to a complete lignin deposition [ 2 ]. (biomedcentral.com)
  • Among the protocols described, the one using hydrogen peroxide followed by application of silane seems the most promising, since it allows increased bond strengths without fiber damage. (bvsalud.org)
  • Saitoh Y* , Ikeshima M, Kawasaki N, MasumotoA, Miwa N. Transient generation of hydrogen peroxide is responsible for carcinostatic effects of hydrogen combined with platinum nanocolloid, together with increases intracellular ROS, DNA cleavages, and proportion of G2/M-phase. (pu-hiroshima.ac.jp)
  • For many years we have been suggesting the simple health benefits of a gentle dilution of 35% food-grade hydrogen peroxide. (gaiaorganics.co.za)
  • Magnesium Peroxide will clear the body and gut from any excess acid and mucous thereby allowing the beneficial oxygenating effects 0f 35% Food Grade Hydrogen Peroxide to be fully absorbed at the cellular level. (gaiaorganics.co.za)
  • Selenium-mediated protection from ascorbate was powered by NADPH from the pentose phosphate pathway. (princeton.edu)
  • Among the defense mechanisms that activate plants to cope with environmental stress situations, it is worth noting the ascorbate-glutathione cycle, a complex metabolic pathway in which a variety of photochemical, chemical and enzymatic steps are involved. (biomedcentral.com)
  • Record the reduction in ascorbate concentration by reading the absorbance at 290 nm continuously for 180 seconds. (prometheusprotocols.net)
  • In vivo, dietary selenium deficiency resulted in significant enhancement of ascorbate activity against glioblastoma xenografts. (princeton.edu)
  • The research hypothesis was that HP promotes alterations in the mineral content of enamel regardless of the peroxide concentration and the number of peroxide applications. (bvsalud.org)
  • cannot be exactly solved for any system, except the very simplest ones, such as the hydrogen atom. (lu.se)
  • Hydrogen peroxide- and glutathione-associated mechanisms of acclima-tory stress tolerance and signaling. (degruyter.com)
  • 1) Saitoh Y* , Yonekura N, Matsuoka D, Matsumoto A. Molecular hydrogen suppresses Porphyromonas gingivalis lipopolysaccharide-induced increases in interleukin-1 alpha and interleukin-6 secretion in human gingival cells. (pu-hiroshima.ac.jp)
  • APX is an integral component of the glutathione-ascorbate cycle. (wikipedia.org)
  • In addition, plants can also dissipate excess excitation energy in PSII antenna as heat through nonphotochemical processes, which involves the xanthophyll cycle using ascorbate (ASC) as the reducing agent [ 4 ]. (biomedcentral.com)
  • 2) Kato S, Saitoh Y , Miwa N. Carcinostatic effects of alkanoyl ascorbate plus platinum nano-colloid and stabilization of the esterolytically resultant ascorbate by hydrogen. (pu-hiroshima.ac.jp)
  • Since the introduction of at-home bleaching in 1989 by Haywood and Heymann 4 , many studies have evaluated the effects of hydrogen and carbamide peroxides on mineralized and dental pulp tissues. (bvsalud.org)
  • The obtained results are broadly consistent with experimental observations and highlight the key role played by ascorbate recycling for plants to adapt to their surrounding environment. (biomedcentral.com)
  • Ascorbate peroxidase has vital defensive role against ROS [ 17 ] and can catalyze the breakdown of H 2 O 2 that is produced by SOD. (hindawi.com)
  • This means that defining an enzyme as an APX is not straightforward, but is usually applied when the specific activity for ascorbate is higher than that for other substrates. (wikipedia.org)
  • Hydrogen peroxide (H 2 O 2 ) plays versatile roles in various biological processes and in responses to stress in plants. (degruyter.com)
  • Ascorbate peroxidase- a hydrogen peroxide-scavenging enzyme in plants.Physiologia Plantarum85: 235-241. (ac.ir)
  • Hiner A, Ruiz J, Lopez JN, Arnao MB, Raven EL, Canovas FG, Acosta M. 2002.Kinetic study of the inactivation of Ascorbate-peroxidase by hydrogen peroxide. (innspub.net)