| Dedicated roles of plastid transketolases during the early onset of isoprenoid biogenesis in pepper fruits1. | |
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MedLine Citation:
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PMID: 9701598 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Isopentenyl diphosphate (IPP), which is produced from mevalonic acid or other nonmevalonic substrates, is the universal precursor of isoprenoids in nature. Despite the presence of several isoprenoid compounds in plastids, enzymes of the mevalonate pathway leading to IPP formation have never been isolated or identified to our knowledge. We now describe the characterization of two pepper (Capsicum annuum L.) cDNAs, CapTKT1 and CapTKT2, that encode transketolases having distinct and dedicated specificities. CapTKT1 is primarily involved in plastidial pentose phosphate and glycolytic cycle integration, whereas CapTKT2 initiates the synthesis of isoprenoids in plastids via the nonmevalonic acid pathway. From pyruvate and glyceraldehyde-3-phosphate, CapTKT2 catalyzes the formation of 1-deoxy-xylulose-5-phosphate, the IPP precursor. CapTKT1 is almost constitutively expressed during the chloroplast-to-chromoplast transition, whereas CapTKT2 is overexpressed during this period, probably to furnish the IPP necessary for increased carotenoid biosynthesis. Because deoxy-xylulose phosphate is shared by the plastid pathways of isoprenoid, thiamine (vitamin B1), and pyridoxine (vitamin B6) biosynthesis, our results may explain why albino phenotypes usually occur in thiamine-deficient plants. |
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Authors:
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F Bouvier; A d'Harlingue; C Suire; R A Backhaus; B Camara |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Plant physiology Volume: 117 ISSN: 0032-0889 ISO Abbreviation: Plant Physiol. Publication Date: 1998 Aug |
Date Detail:
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Created Date: 1998-09-21 Completed Date: 1998-09-21 Revised Date: 2013-04-17 |
Medline Journal Info:
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Nlm Unique ID: 0401224 Medline TA: Plant Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1423-31 Citation Subset: IM |
Affiliation:
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Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique and Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg, France. |
| Data Bank Information | |
Bank Name/Acc. No.:
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GENBANK/Y15781; Y15782 |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Sequence Base Sequence Capsicum / enzymology* DNA, Complementary Hemiterpenes* Isoenzymes / chemistry, metabolism* Molecular Sequence Data Organophosphorus Compounds / metabolism Plants, Medicinal* Plastids / enzymology* Polyisoprenyl Phosphates / biosynthesis* Pyridoxine / biosynthesis Sequence Homology, Amino Acid Thiamine / biosynthesis Transketolase / chemistry, metabolism* |
| Chemical | |
Reg. No./Substance:
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0/DNA, Complementary; 0/Hemiterpenes; 0/Isoenzymes; 0/Organophosphorus Compounds; 0/Polyisoprenyl Phosphates; 358-71-4/isopentenyl pyrophosphate; 59-43-8/Thiamine; 65-23-6/Pyridoxine; EC 2.2.1.1/Transketolase |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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