scholarly journals Characterization of membrane polypeptides from pea leaf peroxisomes involved in superoxide radical generation

1999 ◽  
Vol 337 (3) ◽  
pp. 531-536 ◽  
Author(s):  
Eduardo LÓPEZ-HUERTAS ◽  
Francisco J. CORPAS ◽  
Luisa M. SANDALIO ◽  
Luis A. DEL RÍO
Keyword(s):  
Cytochrome C ◽  
Electron Donor ◽  
Polyclonal Antibodies ◽  
Reductase Activity ◽  
Monodehydroascorbate Reductase ◽  
Peroxisomal Membrane ◽  
Cytochrome C Reductase ◽  
Ferricyanide Reductase ◽  
Sds Page ◽  
O2 Production

The production of superoxide radicals (O2-•) and the activities of ferricyanide reductase and cytochrome c reductase were investigated in peroxisomal membranes from pea (Pisum sativum L.) leaves using NADH and NADPH as electron donors. The generation of O2-• by peroxisomal membranes was also assayed in native polyacrylamide gels using an in situ staining method with NitroBlue Tetrazolium (NBT). When peroxisomal membranes were assayed under native conditions using NADH or NADPH as inducer, two different O2-•-dependent Formazan Blue bands were detected. Analysis by SDS/PAGE of these bands demonstrated that the NADH-induced NBT reduction band contained several polypeptides (PMP32, PMP61, PMP56 and PMP18, where PMP is peroxisomal membrane polypeptide and the number indicates molecular mass in kDa), while the NADPH-induced band was due exclusively to PMP29. PMP32 and PMP29 were purified by preparative SDS/PAGE and electroelution. Reconstituted PMP29 showed cytochrome c reductase activity and O2-• production, and used NADPH specifically as electron donor. PMP32, however, had ferricyanide reductase and cytochrome c reductase activities, and was also able to generate O2-• with NADH as electron donor, whereas NADPH was not effective as an inducer. The reductase activities of, and O2-• production by, PMP32 were inhibited by quinacrine. Polyclonal antibodies against cucumber monodehydroascorbate reductase (MDHAR) recognized PMP32, and this polypeptide is likely to correspond to the MDHAR reported previously in pea leaf peroxisomal membranes.

scholarly journals Immunochemical characterization of NADPH-cytochrome P-450 reductase from Jerusalem artichoke and other higher plants

1989 ◽  
Vol 259 (3) ◽  
pp. 847-853 ◽  
Author(s):  
I Benveniste ◽  
A Lesot ◽  
M P Hasenfratz ◽  
F Durst
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Higher Plants ◽  
Polyclonal Antibodies ◽  
Reductase Activity ◽  
Jerusalem Artichoke ◽  
Cross Reactivity ◽  
Cytochrome C Reductase ◽  
Nadph Cytochrome ◽  
Cytochrome P 450

Polyclonal antibodies were prepared against NADPH-cytochrome P-450 reductase purified from Jerusalem artichoke. These antibodies inhibited efficiently the NADPH-cytochrome c reductase activity of the purified enzyme, as well as of Jerusalem artichoke microsomes. Likewise, microsomal NADPH-dependent cytochrome P-450 mono-oxygenases (cinnamate and laurate hydroxylases) were efficiently inhibited. The antibodies were only slightly inhibitory toward microsomal NADH-cytochrome c reductase activity, but lowered NADH-dependent cytochrome P-450 mono-oxygenase activities. The Jerusalem artichoke NADPH-cytochrome P-450 reductase is characterized by its high Mr (82,000) as compared with the enzyme from animals (76,000-78,000). Western blot analysis revealed cross-reactivity of the Jerusalem artichoke reductase antibodies with microsomes from plants belonging to different families (monocotyledons and dicotyledons). All of the proteins recognized by the antibodies had an Mr of approx. 82,000. No cross-reaction was observed with microsomes from rat liver or Locusta migratoria midgut. The cross-reactivity generally paralleled well the inhibition of reductase activity: the enzyme from most higher plants tested was inhibited by the antibodies; whereas Gingko biloba, Euglena gracilis, yeast, rat liver and insect midgut activities were insensitive to the antibodies. These results point to structural differences, particularly at the active site, between the reductases from higher plants and the enzymes from phylogenetically distant plants and from animals.

Brain Regional Analysis of NADH-Cytochrome C Reductase Activity in Alzheimerʼs Disease

1990 ◽  
Vol 49 (3) ◽  
pp. 206-214 ◽  
Author(s):  
GEORGE S. ZUBENKO ◽  
JOHN MOOSSY ◽  
DIANA CLAASSEN ◽  
A. Julio Martinez ◽  
GUTTI R. RAO
Keyword(s):  
Cytochrome C ◽  
Reductase Activity ◽  
Regional Analysis ◽  
Cytochrome C Reductase ◽  
Nadh Cytochrome

STUDIES ON THE CYTOCHROME OXIDASE AND OXIDATION PATHWAY IN UREDOSPORES OF WHEAT STEM RUST

1961 ◽  
Vol 39 (5) ◽  
pp. 1131-1148 ◽  
Author(s):  
G. A. White ◽  
G. A. Ledingham
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Cytochrome Oxidase ◽  
Reductase Activity ◽  
Oxygen Affinity ◽  
Antimycin A ◽  
Respiratory Enzymes ◽  
Wheat Stem Rust ◽  
Malic Dehydrogenase ◽  
Cytochrome C Reductase

Electron transport to oxygen in a particulate fraction from uredospores of Puccinia graminis var. tritici occurs through a series of carriers similar to those of other fungi and higher plants.Experiments with various enzyme inhibitors and measurements of the oxygen affinity of respiration have shown that cytochrome oxidase mediates the final step in the sequence of electron transfer. The enzyme was localized in a fraction sedimenting at 20,000 g and was typically inhibited by cyanide, azide, and CO-dark, the latter inhibition being light-reversible. Other enzymes present were succinic-cytochrome c reductase, DPNH- and TPNH-cytochrome c reductase, dye reductase, malic dehydrogenase, isocitric dehydrogenase, and glycerol-1-phosphate dehydrogenase. Particulates failed to oxidize DPNH unless an electron acceptor was added. An increase in the activity of several of the respiratory enzymes was noted upon spore germination.Succinic-cytochrome c reductase was only partially sensitive to Antimycin A, HOQNO, and the naphthoquinone, SN 5949. These compounds markedly inhibited a labile portion of the DPNH-cytochrome c reductase activity but had little effect on the stable activity remaining in aged particles. Menadione, but not vitamin K1, stimulated electron transfer. Antimycin A and SN 5949 virtually blocked spore respiration suggesting a "Slater-type" factor in the intact pathway of oxidation.

Temperature Influence on Basal Activity and Induction of Mixed Function Oxygenase Activity in Fundulus heteroclitus

1979 ◽  
Vol 36 (11) ◽  
pp. 1400-1405 ◽  
Author(s):  
John J. Stegeman
Keyword(s):  
Cytochrome C ◽  
Fundulus Heteroclitus ◽  
Reductase Activity ◽  
Control Fish ◽  
Cytochrome C Reductase ◽  
Nadph Cytochrome ◽  
Pyrene Hydroxylase ◽  
Mixed Function Oxygenase ◽  
Cytochrome P 450 ◽  
Nadph Cytochrome C Reductase

Treatment of Fundulus heteroclitus acclimated to 6.5 °C with benzo(a)pyrene did not elicit any change in the levels of hepatic microsomal NADH- or NADPH-cytochrome c reductase activity, nor in the levels of cytochrome P-450 or its catalytic activities. However, the same treatment offish at 16 5 °C resulted in a marked induction of benzo(a)pyrene hydroxylase and NADPH-cytochrome c reductase. Cytochrome P-450 content was also higher in the warm, treated fish and the Soret maximum of reduced, CO-treated microsomes was shifted to the violet. Levels of aminopyrine demethylase and NADH-cytochrome c reductase activities did not show a significant treatment effect. At neither temperature could treated and control fish be distinguished on the basis of in vitro inhibition of benzo(a)pyrene hydroxylase activity by 7,8-benzoflavone. Levels of NADPH-cytochrome c reductase and benzo(a)pyrene hydroxylase activities were greater in control Fundulus acclimated to 6.5 °C than to 16.5 °C, when normalized to microsomal protein, but not when based on body weight. The results indicate that habitat temperature alone may not affect the capacity for initial hydrocarbon metabolism in fish, but that it can strongly influence the induction of cytochrome P-450. Key words: temperature, cytochrome P-450, hydrocarbon metabolism, mixed-function oxygenase, Fundulus heteroclitus

Assignment of estradiol-17β dehydrogenase and of estrone reductase to cytoplasmic structures of porcine endometrium cells

1989 ◽  
Vol 121 (2) ◽  
pp. 161-167 ◽  
Author(s):  
J. Adamski ◽  
W. D. Sierralta ◽  
P. W. Jungblut
Keyword(s):  
Cytochrome C ◽  
Kinetic Data ◽  
Reductase Activity ◽  
Particulate Fraction ◽  
Marker Enzyme ◽  
Structural Element ◽  
Cytochrome C Reductase ◽  
Percoll Gradients ◽  
Cytoplasmic Structures ◽  
Estradiol 17Β

Abstract. Homogenates of porcine endometrium contain substantial activity for the dehydrogenation of estradiol-17β but little for estrone reduction. Both activities are associated with cytoplasmic structures. The dehydrogenase is characterized by a pH 7.7 optimum, Km 2.2 × 10−7 mol/l for estradiol and Km 4.4 × 10−5 mol/l for the cosubstrate NAD+. The corresponding figures for the reductase are pH 6.6, Km 1.1 × 10−6 mol/1 for estrone and Km 2.1 × 10−5 mol/l for the cosubstrate NADPH. The (mitochondrial/lysosomal) 17 000 × g particulate fraction contains a 52-fold higher dehydrogenase than reductase activity. The (microsomal) 200000 × g particulate fraction is only 16-fold richer in dehydrogenase. Isopycnic centrifugations of the two fractions in Percoll gradients reveal that estrone reductase and the coequilibrating marker enzyme cytochrome c reductase occur in constant proportions, whereas the dehydrogenase/cytochrome c reductase ratios are different. Both, the kinetic data and the structural assignments speak in favour of individual enzymes catalyzing the dehydrogenation of estradiol and the reduction of estrone. All gradient fractions exhibiting dehydrogenase activity feature small, electrondense vesicles of 0.15–0.20 μm in diameter as a common structural element which might harbour the dehydrogenase.

scholarly journals Structural and functional relationships of enzyme activities induced by nitrate in barley

1970 ◽  
Vol 119 (4) ◽  
pp. 715-725 ◽  
Author(s):  
John L. Wray ◽  
Philip Filner
Keyword(s):  
Cytochrome C ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Bottom Layer ◽  
Sucrose Density Gradient ◽  
Enzyme Complex ◽  
Cytochrome C Reductase ◽  
Functional Relationships ◽  
Nadh Cytochrome

1. Nitrate induces the development of NADH-nitrate reductase (EC 1.6.6.1), FMNH2–nitrate reductase and NADH–cytochrome c reductase activities in barley shoots. 2. Sucrose-density-gradient analysis shows one band of NADH–nitrate reductase (8S), one band of FMNH2–nitrate reductase activity (8S) and three bands of NADH–cytochrome c reductase activity (bottom layer, 8S and 3.7S). Both 8S and 3.7S NADH–cytochrome c reductase activities are inducible by nitrate, but the induction of the 8S band is much more marked. 3. The 8S NADH–cytochrome c reductase band co-sediments with both NADH–nitrate reductase activity and FMNH2–nitrate reductase activity. Nitrite reductase activity (4.6S) did not coincide with the activity of either the 8S or the 3.7S NADH–cytochrome c reductase. 4. FMNH2–nitrate reductase activity is more stable (t½ 12.5min) than either NADH–nitrate reductase activity (t½ 0.5min) or total NADH–cytochrome c reductase activity (t½ 1.5min) at 45°C. 5. NADH–cytochrome c reductase and NADH–nitrate reductase activities are more sensitive to p-chloromercuribenzoate than is FMNH2–nitrate reductase activity. 6. Tungstate prevents the formation of NADH–nitrate reductase and FMNH2–nitrate reductase activities, but it causes superinduction of NADH–cytochrome c reductase activity. Molybdate overcomes the effects of tungstate. 7. The same three bands (bottom layer, 8S and 3.7S) of NADH–cytochrome c reductase activity are observed irrespective of whether induction is carried out in the presence or absence of tungstate, but only the activities in the 8S and 3.7S bands are increased. 8. The results support the idea that NADH–nitrate reductase, FMNH2–nitrate reductase and NADH–cytochrome c reductase are activities of the same enzyme complex, and that in the presence of tungstate the 8S enzyme complex is formed but is functional only with respect to NADH–cytochrome c reductase activity.

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