Metabolism of hydrogen peroxide in Euglena gracilis Z by L-ascorbic acid peroxidase

Shigeoka, Shigeru; Nakano, Yoshihisa; Kitaoka, Shôzaburô

doi:10.1042/bj1860377

Cited by 136 publications

(63 citation statements)

References 32 publications

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“…The number following the functional categories represents the number of proteins identified within each of them. The list of the corresponding proteins is presented in Supplementary Tables 2 and 3. superoxide dismutase and hydroperoxide reductase, were also accumulated suggesting existence of adaptation processes to environmental stresses (Lengfelder and Elstner, 1979;Shigeoka et al, 1980;Seaver and Imlay, 2001). Similarly, a membrane-associated, ATP-dependent H þ transporter was found, presumably reflecting an acclimation to the low-pH conditions prevailing in the Carnoulès AMD.…”

Section: Metabolite Secretion In Amd By Euglena Mutabilis D Halter Et Almentioning

confidence: 87%

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

et al. 2012

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Euglena mutabilis is a photosynthetic protist found in acidic aquatic environments such as peat bogs, volcanic lakes and acid mine drainages (AMDs). Through its photosynthetic metabolism, this protist is supposed to have an important role in primary production in such oligotrophic ecosystems. Nevertheless, the exact contribution of E. mutabilis in organic matter synthesis remains unclear and no evidence of metabolite secretion by this protist has been established so far. Here we combined in situ proteo-metabolomic approaches to determine the nature of the metabolites accumulated by this protist or potentially secreted into an AMD. Our results revealed that the secreted metabolites are represented by a large number of amino acids, polyamine compounds, urea and some sugars but no fatty acids, suggesting a selective organic matter contribution in this ecosystem. Such a production may have a crucial impact on the bacterial community present on the study site, as it has been suggested previously that prokaryotes transport and recycle in situ most of the metabolites secreted by E. mutabilis. Consequently, this protist may have an indirect but important role in AMD ecosystems but also in other ecological niches often described as nitrogen-limited.

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Section: Metabolite Secretion In Amd By Euglena Mutabilis D Halter Et Almentioning

confidence: 87%

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

et al. 2012

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“…Protein was routinely determined by the procedure described by Bradford (3). However, to report the final specific activity of the purified enzyme, the Lowry method was used (12 (20). The level of the enzyme did vary significantly with the growth phase of the cell increasing during the stationary phase (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The specific activities of each purified enzyme are not compared since each was assayed under different conditions of pH, substrate concentrations, and temperature; the difficulty of comparing published GSH peroxidase activity values has been reviewed by Wendel (26 The enzyme exhibited a relatively low Km for H202 suggesting it might play a role in H202 scavenging in these algae. E. gracilis lacks catalase but does contain L-ascorbic acid peroxidase, an enzyme thought to protect the cells against peroxides generated during photosynthesis (20). Since the levels of GSH peroxidase are not increased by growth in the light (Table I), the enzyme may play a constitutive role in scavenging H202 in the cytoplasmic compartment in cells grown in the dark or light.…”

Section: Methodsmentioning

confidence: 99%

Characterization of a Selenium-Independent Glutathione Peroxidase From Euglena gracilis

Overbaugh

Fall²

1985

Plant Physiol.

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Light or dark grown Euglena gracilis strains contain similar levels of glutathione (GSH) peroxidase. Cells in midstationary phase of growth contained the highest level of the enzyme. The enzyme was purified 280-fold to homogeneity from the permanently bleached strain, E. grailis var bacillaris W3BUL. The native enzyme has a molecular weight of 130,000 as measured by gel permeation chromatography, and contains four subunits (mol wt 31,500) as measured by sodium dodecyl sulfate gel electrophoresis. A variable amount of a higher molecular weight form of the enzyme (approximate mol wt 250,000) was detected but not further characterized. The enzyme has an isoelectric point of 4.7. No selenium could be detected in the purified enzyme. The enzyme is active with H202 and a variety oforpnic hydroperoxides, including 13-hydroperoxylinoleic acid, and is specific for GSH as the thiol substrate. Apparent K,. values for H202, t-butyl hydroperoxide, and GSH were 0.03, 1.5, and 0.7 millimolar, respectively. A comparison of selenium-dependent and selenium-independent GSH peroxidases from various eukaryotic sources is presented.In animals, where these enzymes have been studied most extensively, both Se-dependent and Se-independent GSH peroxidases have been described (26). The Se-dependent enzyme contains a selenocysteine residue in the active site, and is active in reducing H202 as well as organic hydroperoxides. The SEindependent GSH peroxidases are active only with organic hydroperoxides, and are identical with certain GSH transferase isozymes (17 (6), and was quantitated using the procedure of Vioque and Holman (24). Sephacryl S-300 and the chromatofocusing kit containing PBE94 and polybuffer were purchased from Pharmacia. Ampholytes were obtained from BioRad. The ultrafiltration cell and filters were products of Amicon. All other materials were reagent grade.Organisms and Growth Conditions. Euglena strains were obtained as previously described (16) and maintained on Euglena broth (Difco) solidified with 1.5% (w/v) agar. Euglena gracilis Z was grown in an autotrophic medium (9) bubbled with 5% CO2 or air under fluorescent lights at 20°C. For heterotrophic growth, CO2 was replaced by 1.8% (w/v) glucose and cells were grown in the light (photoheterotrophic) or dark (heterotrophic). E. gracilis var bacillaris and the permanently bleached strain W3BUL were grown at 20°C in the defined medium described by Ortiz et al. (14), with either 1.8% (w/v) glucose or 0.2 M ethanol as the carbon source. For enzyme purification purposes, W3BUL was grown routinely in Euglena broth. The cells were harvested in midstationary phase by centrifugation at 8000g, and were washed twice with 20 mm potassium phosphate, pH 7.4, (K buffer) at 20C.Enzyme Purification. The cell pellet was resuspended in 5 to 10 volumes of cold K buffer and twice passed through a French press at 15,000 p.s.i. The homogenate was centrifuged at 40,00Og for 20 min, and the supernatant was used as the crude extract. Throughout the purification of GSH peroxidase, K buffer ...

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“…59) Therefore, a high concentration of AsA was required for its purification from Euglena and plant cells. 58,60) This property may have delayed the discovery of this enzyme. Subsequent studies demonstrated that APX was widely distributed in photosynthetic eukaryotes, including higher plants, but not in prokaryotes.…”

Section: Distribution and Biosynthesis Of Asamentioning

confidence: 99%

“…The new H 2 O 2 -scavenging enzyme, APX, which uses AsA as an electron donor, was firstly purified from Euglena over 30 years ago. 58) This enzyme was shown to be extremely unstable in the absence of AsA. 59) Therefore, a high concentration of AsA was required for its purification from Euglena and plant cells.…”

Section: Distribution and Biosynthesis Of Asamentioning

confidence: 99%

Cellular redox regulation, signaling, and stress response in plants

Shigeoka

Maruta

2014

Bioscience, Biotechnology, and Biochemistry

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Cellular and organellar redox states, which are characterized by the balance between oxidant and antioxidant pool sizes, play signaling roles in the regulation of gene expression and protein function in a wide variety of plant physiological processes including stress acclimation. Reactive oxygen species (ROS) and ascorbic acid (AsA) are the most abundant oxidants and antioxidants, respectively, in plant cells; therefore, the metabolism of these redox compounds must be strictly and spatiotemporally controlled. In this review, we provided an overview of our previous studies as well as recent advances in (1) the molecular mechanisms and regulation of AsA biosynthesis, (2) the molecular and genetic properties of ascorbate peroxidases, and (3) stress acclimation via ROS-derived oxidative/redox signaling pathways, and discussed future perspectives in this field.

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Metabolism of hydrogen peroxide in Euglena gracilis Z by L-ascorbic acid peroxidase

Cited by 136 publications

References 32 publications

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

Characterization of a Selenium-Independent Glutathione Peroxidase From Euglena gracilis

Cellular redox regulation, signaling, and stress response in plants

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