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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1989-6-7
|
| pubmed:abstractText |
Results obtained with isolated intact chloroplasts maintained aerobically under light and dark conditions confirm earlier findings with reconstituted enzyme assays and indicate that the ferredoxin/thioredoxin system functions as a light-mediated regulatory thiol chain. The results were obtained by application of a newly devised procedure in which a membrane-permeable thiol labeling reagent, monobromobimane (mBBr), reacts with sulfhydryl groups and renders the derivatized protein fluorescent. The mBBr-labeled protein in question is isolated individually from chloroplasts by immunoprecipitation and its thiol redox status is determined quantitatively by combining sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorescence measurements. The findings indicate that each member of the ferredoxin/thioredoxin system containing a catalytically active thiol group is reduced in isolated intact chloroplasts after a 2-min illumination. The extents of reduction were FTR, 38%; thioredoxin m, 75% (11-kDa form) and 87% (13-kDa form); thioredoxin f, 95%. Reduction of each of these components was negligible both in the dark and when chloroplasts were transferred from light to dark conditions. The target enzyme, NADP-malate dehydrogenase, also underwent net reduction in illuminated intact chloroplasts. Fructose-1,6-bisphosphatase showed increased mBBr labeling under these conditions, but due to interfering gamma globulin proteins it was not possible to determine whether this was a result of net reduction as is known to take place in reconstituted assays. Related experiments demonstrated that mBBr, as well as N-ethylmaleimide, stabilized photoactivated NADP-malate dehydrogenase and fructose-1,6-bisphosphatase so that they remained active in the dark. By contrast, phosphoribulokinase, another thioredoxin-linked enzyme, was immediately deactivated following mBBr addition. These latter results provide new information on the relation between the regulatory and active sites of these enzymes.
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Bicyclo Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Chlorophyll,
http://linkedlifedata.com/resource/pubmed/chemical/Chloroplast Thioredoxins,
http://linkedlifedata.com/resource/pubmed/chemical/Ferredoxins,
http://linkedlifedata.com/resource/pubmed/chemical/Fluorescent Dyes,
http://linkedlifedata.com/resource/pubmed/chemical/Iron-Sulfur Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Light-Harvesting Protein Complexes,
http://linkedlifedata.com/resource/pubmed/chemical/Oxidoreductases,
http://linkedlifedata.com/resource/pubmed/chemical/Photosynthetic Reaction Center...,
http://linkedlifedata.com/resource/pubmed/chemical/Plant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfhydryl Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Thioredoxins,
http://linkedlifedata.com/resource/pubmed/chemical/ferredoxin-thioredoxin reductase,
http://linkedlifedata.com/resource/pubmed/chemical/monobromobimane
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| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0003-9861
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
15
|
| pubmed:volume |
271
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
223-39
|
| pubmed:dateRevised |
2007-11-15
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| pubmed:meshHeading |
pubmed-meshheading:2653221-Bacterial Proteins,
pubmed-meshheading:2653221-Bicyclo Compounds,
pubmed-meshheading:2653221-Chlorophyll,
pubmed-meshheading:2653221-Chloroplast Thioredoxins,
pubmed-meshheading:2653221-Chloroplasts,
pubmed-meshheading:2653221-Chromatography, Affinity,
pubmed-meshheading:2653221-Darkness,
pubmed-meshheading:2653221-Electrophoresis, Polyacrylamide Gel,
pubmed-meshheading:2653221-Enzyme Activation,
pubmed-meshheading:2653221-Ferredoxins,
pubmed-meshheading:2653221-Fluorescent Dyes,
pubmed-meshheading:2653221-Iron-Sulfur Proteins,
pubmed-meshheading:2653221-Light,
pubmed-meshheading:2653221-Light-Harvesting Protein Complexes,
pubmed-meshheading:2653221-Oxidation-Reduction,
pubmed-meshheading:2653221-Oxidoreductases,
pubmed-meshheading:2653221-Photosynthetic Reaction Center Complex Proteins,
pubmed-meshheading:2653221-Plant Proteins,
pubmed-meshheading:2653221-Precipitin Tests,
pubmed-meshheading:2653221-Sulfhydryl Compounds,
pubmed-meshheading:2653221-Thioredoxins
|
| pubmed:year |
1989
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| pubmed:articleTitle |
Evidence for function of the ferredoxin/thioredoxin system in the reductive activation of target enzymes of isolated intact chloroplasts.
|
| pubmed:affiliation |
Division of Molecular Plant Biology, University of California, Berkeley 94720.
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| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.
|