| | 1 | Author
| G. Renger, R. H. Agem Ann, W.F J V Erm Aas | Requires cookie* | | | Title
| Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts  | | | | Abstract
| The effect o f specific proteolytic enzymes on variable fluorescence, p-benzoquinone-m ediated oxygen evolution, PS II herbicide (atrazine and brom oxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts. It was found that: 1. Trypsin and a lysine-specific protease effectively reduce the m axim um chlorophyll-a flu o rescence yield, whereas the initial fluorescence remains alm ost constant. At the sam e number o f enzymatic activity units both proteases have practically the sam e effect. 2 Trypsin and a lysine-specific protease inhibit the /»-benzoquinone-m ediated flash-induced oxygen evolution with trypsin being markedly more effective at the sam e num ber o f activity units o f both enzymes. Unstacked thylakoids exhibit a higher sensitivity to proteolytic degrada tion by both enzymes. 3. Trypsin and a lysine-specific protease reduce the binding capacity o f [14C]atrazine, but enhance that o f [l4C]bromoxynil (at long incubation tim es trypsin treatm ent also impairs bromoxynil binding). At the same specific activity a m arkedly longer treatm ent is required for the lysine-specific protease in order to achieve the same degree o f m odification as w ith trypsin. 4. Trypsin was found to attack the rapidly-turned-over 32 kD a-protein severely, whereas the lysine-specific protease does not m odify this polypeptide. On the other hand, the lysine-specific protease attacks the light harvesting com plex II. 5. Under our experimental conditions an arginine-specific protease did not affect chlorophyll-a fluorescence yield, /?-benzoquinone-mediated oxygen evolution, herbicide binding and the p oly peptide pattern. Based on these results a m echanism is proposed in w hich an as yet unidentified polypeptide with exposable lysine residues, as well as the lysine-free "Q B-protein" regulate the electron transfer from Q ^ to Q B and are involved in herbicide binding. | | | |
Reference
| Z. Naturforsch. 39c, 362—367 (1984); received Decem ber 1 1983 | | | |
Published
| 1984 | | | |
Keywords
| Chloroplasts, Proteolytic Enzymes, Fluorescence, Oxygen Evolution, H erbicide Binding | | | |
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| default:Reihe_C/39/ZNC-1984-39c-0362.pdf | | | | Identifier
| ZNC-1984-39c-0362 | | | | Volume
| 39 | |
| 2 | Author
| Ulrike Strohmeier, ChristianG. Erdes3, Wolfgang Lockaub | Requires cookie* | | | Title
| Proteolysis in Heterocyst-Forming Cyanobacteria: Characterization of a Further Enzyme with Trypsin-Like Specificity, and of a Prolyl Endopeptidase from Anabaena variabilis | | | | Abstract
| of the cyanobacterium Anabaena variabilis ATCC 29413 and an en gineered mutant that lacks an intracellular protease cleaving after Lys and Arg (Maldener, Lockau, Cai, and Wolk, Mol. Gen. Genet. 225, 113-120 (1991)) were separated by ion ex change chromatography, and protease profiles determined using azocasein, Na-benzoyl-D,L-arginine-4-nitroanilide and N-carbobenzoxy-glycyl-L-proline-4-nitroanilide as substrates. A second enzyme cleaving at the carboxyl side of lysine and arginine, and a prolyl endopepti dase were detected, enriched and characterized. Both proteolytic enzymes appear to be located in the periplasm. | | | |
Reference
| Z. Naturforsch. 49c, 70—78 (1994); received September 29/December 81993 | | | |
Published
| 1994 | | | |
Keywords
| Anabaena variabilis, Cyanobacterium, Heterocysts, Proteolytic Enzymes, Prolyl Endopeptidase Soluble extracts | | | |
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| default:Reihe_C/49/ZNC-1994-49c-0070.pdf | | | | Identifier
| ZNC-1994-49c-0070 | | | | Volume
| 49 | |
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