scholarly journals Kinetics and mechanisms of catalase in peroxisomes of the mitochondrial fraction

1971 ◽  
Vol 122 (2) ◽  
pp. 225-233 ◽  
Author(s):  
B. Chance ◽  
N. Oshino
Keyword(s):  
Hydrogen Peroxide ◽  
Rat Liver ◽  
Fold Increase ◽  
Mitochondrial Fraction ◽  
Hydrogen Donor ◽  
Urate Oxidase ◽  
Mitochondrial Fractions ◽  
Hydrogen Peroxide Generation ◽  
State 1

1. The primary intermediate of catalase and hydrogen peroxide was identified and investigated in peroxisome-rich mitochondrial fractions of rat liver. On the basis of kinetic constants determined in vitro, it is possible to calculate with reasonable precision the molecular statistics of catalase action in the peroxisomes. 2. The endogenous hydrogen peroxide generation is adequate to sustain a concentration of the catalase intermediate (pm/e) of 60–70% of the hydrogen peroxide saturation value. Total amount of catalase corresponds to 0.12–0.15nmol of haem iron/mg of protein. In State 1 the rate of hydrogen peroxide generation corresponds to 0.9nmol/min per mg of protein or 5′ of the mitochondrial respiratory rate in State 4. 3. Partial saturation of the catalase intermediate with hydrogen peroxide (pm/e) in the mitochondrial fraction suggests its significant peroxidatic activity towards its endogenous hydrogen donor. A variation of this value (pm/e) from 0.3 in State 4 to 0 under anaerobic conditions is observed. 4. For a particular preparation the hydrogen peroxide generation rate in the substrate-supplemented State 4 corresponds to 0.17s-1 (eqn. 6), the hydrogen peroxide concentration to 2.5nm and the hydrogen-donor concentration (in terms of ethanol) to 0.12mm. The reaction is 70% peroxidatic and 30′ catalatic. 5. A co-ordinated production of both oxidizing and reducing substrates for catalase in the mitochondrial fraction is suggested by a 2.2-fold increase of hydrogen peroxide generation and a threefold increase in hydrogen-donor generation in the State 1 to State 4 transition. 6. Additional hydrogen peroxide generation provided by the urate oxidase system of peroxisomes (8–12nmol of uric acid oxidized/min per mg of protein) permits saturation of the catalase with hydrogen peroxide to haem occupancy of 40′ compared with values of 36′ for a purified rat liver catalase ofk1=1.7×107m-1·s-1 and k′4=2.6×107m-1· s-1(Chance, Greenstein & Roughton, 1952). 7. The turnover of the catalase ethyl hydrogen peroxide intermediate (k′3) in the peroxisomes is initially very rapid since endogenous hydrogen peroxide acts as a hydrogen donor. k′3 decreases fivefold in the uncoupled state of the mitochondria.

scholarly journals Biocontrol Activity and Primed Systemic Resistance by Compost Water Extracts Against Anthracnoses of Pepper and Cucumber

2011 ◽  
Vol 101 (6) ◽  
pp. 732-740 ◽  
Author(s):  
Mee Kyung Sang ◽  
Ki Deok Kim
Keyword(s):  
Hydrogen Peroxide ◽  
Fungal Pathogens ◽  
Systemic Resistance ◽  
Plant Responses ◽  
Pr Genes ◽  
Water Extracts ◽  
Pepper Leaves ◽  
Related Enzyme ◽  
Hydrogen Peroxide Generation

We investigated direct and indirect effects of compost water extracts (CWEs) from Iljuk-3, Iljuk-7, Shinong-8, and Shinong-9 for the control of anthracnoses caused by Colletotrichum coccodes on pepper and C. orbiculare on cucumber. All tested CWEs significantly (P < 0.05) inhibited in vitro conidial germination and appressorium formation of the fungal pathogens; however, DL-β-amino-n-butyric acid (BABA) failed to inhibit the conidial development of the pathogens. Direct treatments of the CWEs and BABA on pepper and cucumber leaves at 1 and 3 days before or after inoculation significantly (P < 0.05) reduced anthracnose severities; Iljuk-3, Shinong-9, and BABA for pepper and Iljuk-7 for cucumber had more protective activities than curative activities. In addition, root treatment of CWEs suppressed anthracnoses on the plants by the pathogens; however, CWE treatment on lower leaves failed to reduce the diseases on the upper leaves of the plants. The CWE root treatments enhanced not only the expression of the pathogenesis-related (PR) genes CABPR1, CABGLU, CAChi2, CaPR-4, CAPO1, and CaPR-10 in pepper and PR1-1a, PR-2, PR-3, and APOX in cucumber but also the activity of β-1,3-glucanase, chitinase, and peroxidase and the generation of hydrogen peroxide in pepper and cucumber under pathogen-inoculated conditions. However, the CWE treatments failed to induce the plant responses under pathogen-free conditions. These results indicated that the CWEs had direct effects, reducing anthracnoses by C. coccodes on pepper leaves and C. orbiculare on cucumber leaves through protective and curative effects. In addition, CWE root treatments could induce systemic resistance in the primed state against pathogens on plant leaves that enhanced PR gene expression, defense-related enzyme production, and hydrogen peroxide generation rapidly and effectively immediately after pathogen infection. Thus, the CWEs might suppress anthracnoses on leaves of both pepper and cucumber through primed (priming-mediated) systemic resistance.

scholarly journals LIGHT MICROSCOPIC STUDY OF THE PEROXIDATIC ACTIVITY OF CATALASE IN FORMALDEHYDE-FIXED RAT LIVER

1969 ◽  
Vol 17 (9) ◽  
pp. 585-590 ◽  
Author(s):  
KEI-ICHI HIRAI
Keyword(s):  
Hydrogen Peroxide ◽  
Microscopic Study ◽  
Rat Liver ◽  
Incubation Medium ◽  
Histochemical Staining ◽  
Hydrogen Donor ◽  
Peroxidatic Activity ◽  
Light Microscopic Study ◽  
Parenchymal Cells

The peroxidatic activity of rat liver catalase was demonstrated by histochemical staining with 3,3'-diaminobenzidine as hydrogen donor. The activity was so weak that its location was hard to identify in formaldehyde-fixed cells, although high catalatic activity was present, as evidenced by the production of bubbles upon the addition of hydrogen peroxide to the incubation medium. Pretreatment of fixed sections for 60 min at 37°C with formamide, urea or trypsin enhanced the peroxidatic activity significantly. The reaction granules scattered throughout the cytoplasm of the parenchymal cells probably correspond to the peroxisomes.

Metabolism of n-hexane by rat liver and extrahepatic tissues and the effect of cytochrome P-450 inducers

1997 ◽  
Vol 16 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Sarah J Crosbie ◽  
PG Blain ◽  
Faith M Williams
Keyword(s):  
Skeletal Muscle ◽  
Rat Liver ◽  
Fold Increase ◽  
Rat Tissues ◽  
Human Cytochrome ◽  
Extrahepatic Tissues ◽  
Mass Spectometry ◽  
Fast Twitch ◽  
Cytochrome P 450

1 The in vitro metabolism ofn-hexane was studied in rat liver, lung, brain and skeletal muscle microsomes and in microsomes prepared from cell lines expressing human cytochrome P-450 2E1 or 2B6. The hydro xylated metabolites ofn-hexane were quantified by gas chromatography-mass spectometry. 2 Rat liver and extensor digitorum longus (EDL, fast- twitch skeletal muscle) microsomes and the CYP 2B6 microsomes produced the pre-neurotoxic metabolite of n-hexane, 2-hexanol as a major metabolite in contrast to the other rat tissues examined. 3 Inhibition of 2- and 3-hexanol production from n- hexane by rat lung microsomes using metyrapone, an inhibitor of cytochrome P-450 2B1 activity, resulted in almost complete inhibition of lung microsomal activ ity. 4 Production of all three hexanols was significantly increased with phenobarbital-induced rat liver micro somes, with a 10-fold increase in 2- and 3-hexanol production. A slight increase in 2-hexanol production with phenobarbital-induced rat EDL and brain micro somes was observed. No increase in n-hexane meta bolism was noted following induction with β- naphthoflavone or with ethanol.

scholarly journals Effects of Cobalt on the Renal Erythropoietic Factor and Kidney Hydrolase Activity in the Rat

Blood ◽  
1973 ◽  
Vol 42 (6) ◽  
pp. 893-905 ◽  
Author(s):  
Robert J. Smith ◽  
James W. Fisher
Keyword(s):  
Enzyme Inhibitors ◽  
Mitochondrial Fraction ◽  
Hydrolase Activity ◽  
Marker Enzyme ◽  
Factor Activity ◽  
Rat Serum ◽  
Mitochondrial Fractions ◽  
Normal Rat ◽  
Mitochondrial Extract

Abstract In an experiment to determine the effects of cobalt on the renal erythropoietic factor and kidney hydrolase activity in the rat we obtained the following results: Cobalt produced significant increases in renal erythropoietic factor activity and plasma levels of erythropoietin which reached peak activity 12 hr after treatment. It also produced an increase in the activity of renal hydrolases, cathepsins A and B, which paralleled the increase in renal erythropoietic factor activity. Enzyme inhibitors which are specific for proteases, esterases, and metalloenzymes inhibited the activity of the renal erythropoietic factor in vitro. Polycythemic mice exposed to 7- and 8-day posthypoxic intervals still retained their ability to respond to in vitro generated erythropoietin when compared to mice treated on the fourth posthypoxic day. The erythropoietic activity generated by the light mitochondrial extract—normal rat serum (LME-NRS) reaction mixture was blocked by the antibody to erythropoietin. The relative concentrations of smooth and rough endoplasmic reticulum (microsomes) and vesicles (lysosomes) were approximately the same in the light mitochondrial fractions of kidneys from normal and cobalt-treated rats. Marker enzyme studies revealed primarily alkaline phosphatase activity in the light mitochondrial fraction. These studies correlate with electron micrographs of the LME which indicate a fraction composed mainly of microsomes. In addition, these data suggest a possible relationship between renal lysosomal hydrolase activity and the renal erythropoietic factor (Erythrogenin).

Properties of skeletal muscle mitochondria isolated from subsarcolemmal and intermyofibrillar regions

1993 ◽  
Vol 264 (2) ◽  
pp. C383-C389 ◽  
Author(s):  
A. M. Cogswell ◽  
R. J. Stevens ◽  
D. A. Hood
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Mitochondrial Protein ◽  
Mitochondrial Fraction ◽  
Biochemical Properties ◽  
Leucine Incorporation ◽  
Mitochondrial Protein Synthesis ◽  
Skeletal Muscle Mitochondria ◽  
Mitochondrial Fractions

Two mitochondrial fractions, termed intermyofibrillar (IMF) and subsarcolemmal (SS), were isolated from skeletal muscle, and their biochemical properties were related to differences in respiration and mitochondrial protein synthesis. State III respiration was 2.3- to 2.8-fold greater in IMF than in SS mitochondria. Site 1 inhibition of respiration with rotenone reduced this difference to 1.4-fold. When sites 1 and 2 were inhibited with antimycin, the 1.4-fold differences remained. The activities of cytochrome-c oxidase (CYTOX) and succinate dehydrogenase (SDH) could account for some of these differences, since CYTOX was 20% greater (P < 0.05) in IMF mitochondria, and SDH was 40% greater (P < 0.05) in SS mitochondria. Cytochromes a, b, c, and c1 contents were similar in the two fractions. Cardiolipin (CL) content was higher (P < 0.05) in SS mitochondria, indicating a less dense mitochondrial fraction with respect to CL. In vitro [3H]leucine incorporation was 1.8-fold higher (P < 0.05) in IMF than in SS mitochondria. Thus compositional differences between IMF and SS fractions exist, perhaps representing mitochondria at different stages of biogenesis. The biochemical and functional differences could not solely be due to differences in mitochondrial protein synthesis but could also be due to nuclear-directed protein synthesis specific to each mitochondrial fraction.

scholarly journals Heterogeneity of rat liver mitochondrial fractions and the effect of tri-iodothyronine on their protein turnover

1970 ◽  
Vol 118 (1) ◽  
pp. 111-121 ◽  
Author(s):  
S. S. Katyare ◽  
P. Fatterpaker ◽  
A. Sreenivasan
Keyword(s):  
Rat Liver ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Heavy Fraction ◽  
Rat Liver Mitochondria ◽  
Turnover Rates ◽  
Loosely Coupled ◽  
Mitochondrial Fractions ◽  
Isoelectric Ph

1. Rat liver mitochondria were separated into heavy, light and fluffy fractions by differential centrifugation under standard conditions. 2. All mitochondrial fractions possessed soluble as well as membrane-bound enzymes typical of mitochondria. 3. The heavy fraction represented the stable mitochondrial structures and the fluffy particles appear to be loosely coupled. 4. The light mitochondrial fraction lacked the ability of coupled phosphorylation. 5. A study of mobility and isoelectric pH indicated a similarity in the basic membrane structure of all the mitochondrial fractions. 6. The turnover rates of proteins in the heavy and fluffy particles were almost identical; however, this rate was rapid for the light mitochondrial fraction. 7. On treatment with 3,3′,5-tri-iodo-l-thyronine, succinoxidase activity was maximally stimulated much earlier in the light mitochondrial fraction than in the heavy fraction. The activity of the fluffy particles, however, remained almost unaffected. 8. Malate dehydrogenase activity in all the mitochondrial fractions was stimulated only at 40h after tri-iodothyronine treatment. 9. The pattern of incorporation of dl-[1-14C]leucine in vivo in the tri-iodothyronine-treated animals indicated a rapid initial incorporation and high synthetic ability of the light mitochondrial fraction. 10. The turnover pattern of proteins of the mitochondrial fractions from animals receiving repeated doses of tri-iodothyronine was remarkably different from the normal pattern and suggested that preformed soluble protein units may be incorporated in the light mitochondrial fraction during maturation to form the stable heavy mitochondria. 11. The amount of light-mitochondrial proteins decreased by 40% on thyroidectomy and increased by 160% on treatment with tri-iodothyronine. 12. The possible significance of these results is discussed in relation to mitochondrial genesis.

scholarly journals Bisphenol A increases hydrogen peroxide generation by thyrocytes both in vivo and in vitro

2018 ◽  
Vol 7 (11) ◽  
pp. 1196-1207 ◽  
Author(s):  
Maurício Martins da Silva ◽  
Lueni Lopes Felix Xavier ◽  
Carlos Frederico Lima Gonçalves ◽  
Ana Paula Santos-Silva ◽  
Francisca Diana Paiva-Melo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Bisphenol A ◽  
Thyroid Cell ◽  
Mrna Levels ◽  
Iodide Uptake ◽  
Hydrogen Peroxide Generation ◽  
Rat Thyroid ◽  
The Impact

Bisphenol A (BPA) is the most common monomer in polycarbonate plastics and an endocrine disruptor. Though some effects of BPA on thyroid hormone (TH) synthesis and action have been described, the impact of this compound on thyroid H2O2 generation remains elusive. H2O2 is a reactive oxygen species (ROS), which could have deleterious effect on thyrocytes if in excess. Therefore, herein we aimed at evaluating the effect of BPA exposition both in vivo and in vitro on H2O2 generation in thyrocytes, besides other essential steps for TH synthesis. Female Wistar rats were treated with vehicle (control) or BPA 40 mg/kg BW for 15 days, by gavage. We then evaluated thyroid iodide uptake, mediated by sodium-iodide symporter (NIS), thyroperoxidase (TPO) and dual oxidase (DOUX) activities (H2O2 generation). Hydrogen peroxide generation was increased, while iodide uptake and TPO activity were reduced by BPA exposition. We have also incubated the rat thyroid cell line PCCL3 with 10−9 M BPA and evaluated Nis and Duox mRNA levels, besides H2O2 generation. Similar to that found in vivo, BPA treatment also led to increased H2O2 generation in PCCL3. Nis mRNA levels were reduced and Duox2 mRNA levels were increased in BPA-exposed cells. To evaluate the importance of oxidative stress on BPA-induced Nis reduction, PCCL3 was treated with BPA in association to N-acetylcysteine, an antioxidant, which reversed the effect of BPA on Nis. Our data suggest that BPA increases ROS production in thyrocytes, what could lead to oxidative damage thus possibly predisposing to thyroid disease.

A Mitochondrially Targeted Nitroxide JP4-039 Protects and Mitigates against Total Body Irradiation Induced Hematopoietic Syndrome

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4721-4721 ◽  
Author(s):  
Michael W Epperly ◽  
Joshua G Pierce ◽  
Tracy Dixon ◽  
Darcy Franicola ◽  
Suhua Nie ◽  
...  
Keyword(s):  
Total Body Irradiation ◽  
Fold Increase ◽  
Linear Quadratic ◽  
Mitochondrial Fractions ◽  
High Concentrations ◽  
Total Body ◽  
Induced Apoptosis ◽  
In Vivo Effects

Abstract Nitroxides are efficient scavengers of free radicals and have been proposed for use as radioprotective agents. To circumvent the need for high concentrations for in vivo effects, and to target drugs to the mitochondria to prevent ionizing irradiation-induced apoptosis, we tested a family of compounds based on combining a hemi-gramicidin linker to a nitroxide. One small molecule (JP4-039) produced a 32-fold increased mitochondrial nitroxide localization in 32D cl 3 cells in vitro after one hour incubation at 37°C compared to the unlinked nitroxide tempo at 10uM. The cells were lyzed by rapidly freezing then thawing, followed by centrifugation to yield the nuclear, cytoplasmic, and mitochondrial fractions. EPR was used to quantitate nitroxide in each JP4-039 or tempo treated cell fraction. There was a 32-fold increase in the nitroxide signal for JP4-039 accumulation in the mitochondria compared to the nitroxide tempo. Irradiation survival curves were performed by incubating 32D cl 3 murine hematopoietic progenitor cells in JP4-039 or tempo (1 μM) for one hour before irradiation or by addition immediately following irradiation. The cells were irradiated to doses ranging from 0 to 8 Gy, suspended in methylcellulose-containing media, incubated for seven days at 37°C and colonies of greater than 50 cells were scored. The data was analyzed using linear quadratic and single-hit, multi-target models. Incubation of 32D cl 3 cells in JP4-039 for one hour prior to irradiation resulted in a significant increase in Do to 2.25 ± 0.11 Gy compared to 1.19 ± 0.13 Gy for 32D cl 3 cells alone or 1.32 ± 0.09 Gy for 32D cl 3 cells incubated in tempo (p=0.0042 or 0.0073, respectively). Similar results were achieved giving JP4-039 after irradiation with a Do of 1.97 ± 0.01 Gy (p &lt; 0.0001). To test effectiveness in vivo, C57BL/6NHsd female mice were injected intraperitoneally with JP4-039 or tempo (10 mg/kg) 10 minutes before (or four hours after) total body irradiation to the LD 75/30 dose of 9.75 Gy. Mice were monitored and those moribund from the hematopoietic syndrome were sacrificed. Mice injected with 10 mg/kg JP4-039 before irradiation had a significant increase in survival of 60% compared to 28% for control irradiated mice (p = 0.0005) or 44% for tempo treated mice (p = 0.2252). JP4-039 given after irradiation had a survival of 53% at 30 days after irradiation (p = 0.0474). Thus, JP4-039, a mitochondrial targeted nitroxide, is an effective radioprotector, and mitigator.

P XVII A.13 Ex vivo and in vitro unscheduled DNA synthesis (UDS) assays in rat liver with hydrogen peroxide (H2O2)

1997 ◽  
Vol 379 (1) ◽  
pp. S168-S169 ◽  
Author(s):  
J.-F. Régnier ◽  
C. Clare ◽  
J. de Gerlache ◽  
G. Malinverno ◽  
W. Mayr ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Synthesis ◽  
Rat Liver ◽  
Ex Vivo ◽  
Unscheduled Dna Synthesis
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