| | 2 | Author
| Ian Fry, George Papageorgiou, Elisha Tel-Or, Lester Packer | Requires cookie* | | | Title
| Reconstitution of a System for H 2 Evolution with Chloroplasts, Ferredoxin, and Hydrogenase  | | | | Abstract
| Continuous light-dependent H2 production was studied in a reconstituted in vitro system using S pin acea oleracea chloroplasts, C lostridiu m pasteurianum hydrogenase and S piru lin a m axim a fer redoxin. Photosystem Il-dependent production at 30 °C is 60 —70 /^mol H2/mg chlorophyll. At | | | |
Reference
| (Z. Naturforsch. 32c, 110 [1977]; received December 1 1976) | | | |
Published
| 1977 | | | |
Keywords
| Biophotolysis, H2 Production, Hydrogenase, Ferredoxin, Chloroplasts | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/32/ZNC-1977-32c-0110.pdf | | | | Identifier
| ZNC-1977-32c-0110 | | | | Volume
| 32 | |
| 3 | Author
| R. G. Binder, B. R. Selman | Requires cookie* | | | Title
| Ferredoxin Catalyzed Cyclic Photophosphorylation: Reversal of Dibromothymoquinone Inhibition by N ,N ,N ',N '-T etram ethyl- /j-phenylenediamine | | | | Abstract
| Conditions for washed, spinach thylakoid membranes to catalyze cyclic phosphorylation using ferredoxin as the cofactor for electron transfer have been re-examined. It was found necessary to ''redox poise" the system; however, the best method to accomplish the poising seemed to be the use of a reductant (glucose-6-phosphate) and not by optimizing the rate of phosphorylation with 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). Under these conditions, ferredoxin catalyzed cyclic phosphorylation was found to be sensitive to the inhibitors antimycin A and dibromothymo quinone (DBM IB). The inhibition of ferredoxin catalyzed cyclic phosphorylation by DBMIB, but not by antimycin A, was completely reversed by N, N, N', N'-tetramethyl-p-phenylenediamine (TM PD). These data are taken as further support for the function of plastoquinone in ferredoxin catalyzed cyclic phosphorylation. The effect of TMPD in reversing the DBMIB inhibition is inter preted as the formation of a TMPD bypass on the internal side of the thylakoid membrane around the DBMIB site of inhibition. | | | |
Reference
| Z. Naturforsch. 33c, 261—265 (1978); received November 22 1977 | | | |
Published
| 1978 | | | |
Keywords
| Cyclic Phosphorylation, Chloroplasts, Ferredoxin, Dibromothymoquinone, Phenylenediamine, Photosynthesis | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/33/ZNC-1978-33c-0261.pdf | | | | Identifier
| ZNC-1978-33c-0261 | | | | Volume
| 33 | |
| 5 | Author
| VickiD. Breazeale, BobB. Buchanan, RicardoA. Wolosiuk | Requires cookie* | | | Title
| Chloroplast Sedoheptulose 1,7-Bisphosphatase: Evidence for Regulation by the Ferredoxin/Thioredoxin System | | | | Abstract
| 1. A substrate-specific sedoheptulose-l,7-bisphosphatase has been found in chloroplasts and separated from its fructose-1,6-bisphosphatase counterpart. Experiments with antibodies indicate that the two enzymes are structurally different. 2. Activity of the sedoheptulose-l,7-bisphosphatase enzyme was dependent on M g i+ and a reductant. The most effective reductant tested was thioredoxin that was reduced either photochemi-cally via ferredoxin with chloroplasts or chemically with dithiothreitol. Dithiothreitol added alone also activated the enzyme, but reduced glutathione or 2-mercaptoethanol did not. The thioredoxin-activated enzyme was deactivated by oxidized glutathione. 3. The results suggest that the new substrate-specific sedoheptulose-l,7-bisphosphatase depends on light for activity and resembles certain other regulatory enzymes of the reductive pentose phos phate cycle in its mode of regulation. | | | |
Reference
| Z. Naturforsch. 33c, 521 (1978); received M ay 16 1978 | | | |
Published
| 1978 | | | |
Keywords
| Sed-P2ase, Ferredoxin, Thioredoxin, Enzyme Regulation | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/33/ZNC-1978-33c-0521.pdf | | | | Identifier
| ZNC-1978-33c-0521 | | | | Volume
| 33 | |
| 7 | Author
| C. Hristof Klugham, Er, Ulrich Schreiber | Requires cookie* | | | Title
| Analysis of Light-Induced Absorbance Changes in the Near-Infrared Spectral Region I. Characterization of Various Components in Isolated Chloroplasts | | | | Abstract
| Light-induced absorbance changes in the near-infrared (N IR) spectral region (7 0 0 -9 5 0 nm) are analyzed in isolated spinach chloroplasts using pulsed light-emitting diodes as modulated measuring light sources. With chloroplasts under coupled conditions the light-induced signal is dominated by a relatively slow scattering change displaying a flat difference spectrum. More specific changes can be distinguished by faster induction and relaxation kinetics and in the presence o f valinomycin/nigericin which prevents scattering changes. Besides the dominant P700 change, with a narrow bleaching band around 703 nm and a broad absorbance increase between 750 and 850 nm (peak at 815 nm) the following absorbance changes were identified in the NIR: 1) An absorbance increase caused by plastocyanin (PC) oxidation, with a relatively flat spectrum. 2) An absorbance decrease gaining amplitude towards longer wavelengths, which reflects reduction o f a low potential acceptor o f PS I different from ferredoxin. 3) A field indicating absorbance decrease peaking around 730 nm, the properties o f which correspond to those o f P 515. 4) An uncoupler insensitive absorbance decrease stimulated by dark adaptation and anaero bic conditions, the difference spectrum o f which resembles that o f ferredoxin reduction. The relative contributions o f P700 and PC to the overall oxidized-reduced difference spec trum are determined by redox titration. At 706 nm, 815 nm and 950 nm the P 700/PC is -119/ 19, 67/37 and 31/69, respectively. From these ratios and the molar extinction coefficients a molar P 700/PC stoichiometry o f 1 /3 is determined. | | | |
Reference
| Z. Naturforsch. 46c, 233 (1991); received November 19 1990/January 2 1991 | | | |
Published
| 1991 | | | |
Keywords
| Plastocyanin, Membrane Potential, Ferredoxin, Light Scattering, Photosynthesis | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/46/ZNC-1991-46c-0233.pdf | | | | Identifier
| ZNC-1991-46c-0233 | | | | Volume
| 46 | |
| 8 | Author
| Hermann Bothe, Klaus-Peter Häger | Requires cookie* | | | Title
| Electron Transport to Assimilatory Nitrate Reductase in A zotobacter vinelandii | | | | Abstract
| Assimilatory nitrate reductase was particle-bound in extracts from Azotobacter vinelandii. Nitrate reduction by particle fractions was dependent on NADPH and a particle-bound electron carrier. When the enzyme was solubilized from the particles by treatment with detergents, the particle-bound electron carrier could be substituted by ferredoxin or flavodoxin. Flavodoxin reduced at the expense of photoreduced deazaflavin was much more efficient than ferredoxin in transferring electrons to nitrate reductase. The addition o f both ferredoxin and flavodoxin to the assays with photoreduced deazaflavin gave additive effects. With the solubilized enzyme, NADPH only poorly supported nitrate reduction even after the addition of electron carriers. The experiments indicate that A. vinelandii utilizes an electron transport chain between NADPH and nitrate reductase with some properties similar to those described for the generation of reductants to nitrogenase. | | | |
Reference
| Z. Naturforsch. 36c, 1030—1035 (1981); received July 171981 | | | |
Published
| 1981 | | | |
Keywords
| Assimilatory Nitrate Reductase, Ferredoxin, Flavodoxin, Electron Transport to Nitrate Reductase, Azotobacter vinelandii | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/36/ZNC-1981-36c-1030.pdf | | | | Identifier
| ZNC-1981-36c-1030 | | | | Volume
| 36 | |
|
