| Abstract Detail
Secondary Metabolism Kobayashi, Naoko [1], DellaPenna, Dean [2]. Tocopherol recycling reaction in Arabidopsis thaliana. Tocopherols (Vitamin E) are lipid-soluble antioxidants synthesized by all plants and many cyanobacteria. Genes encoding the main tocopherol biosynthetic pathway have now been isolated primarily from mutant analyses in Arabidopsis thaliana, and used to successfully engineer the content of tocopherols and biosynthetic intermediates in plants. Tocopherols play an important role as antioxidants that scavenge single oxygen and quench and scavenge other reactive oxygen species including lipid peroxy radicals. In these processes, tocopherols can transfer a single electron and the resulting radicals can be reversibly reduced back to the corresponding tocopherol. Alternatively, a tocopherol radical (e.g. α-tocopherol radical) can be further oxidized to products such as α-tocopherolquinone (TQ), epoxy-α-tocopherolquinone and α-tocopherolhydroquinone (TQH2). Unlike animals, plants can synthesize tocopherols and it is therefore possible that tocopherols might be regenerated from such oxidation products. To address this subject, we have used isolated chroloplasts from wild type (Col) and the tocopherol-deficient vte1 mutant in combination with radiolabeled α-TQ to detect whether α-tocopherol can be regenerated or any other compounds formed. In such reaction formation of radiolabled α-tocopherol could be detected at levels four times higher in Col than in vte1, which was near background. We present evidence supporting a reaction sequence for regeneration of α-tocopherol from α-TQ in chloroplast extracts of Col.
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1 - Mishigan State University, Dept. of Biochemistry and Molecular Biology, Biochemistry Building Room 201, East Lansing, MI, 48823, USA
2 - Michigan State University, Dept. of Biochemistry and Molecular Biology
Keywords:
tocopherol
Tocopherol recycling system.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P20017
Abstract ID:302 |
