Plant Metabolism of Xenobiotics

植物螯合素合成酶不仅催化植物螯合素的重金属依赖性合成，而且还作为植物中葡糖缀合物周转的关键步骤，g-谷氨酰-半胱氨酰缀合物形成的催化剂。最近通过体外分析分配了后一种功能。该项目现在建议在体内测试和证实新发现的PCS功能。分析将集中在拟南芥，使用植物，原生质体和植物细胞培养。将分析PCS受损或缺乏PCS的拟南芥突变体的谷胱甘肽缀合物周转和表型改变。此外，计划瞬时调节植物螯合素合酶基因表达以评估其功能。将检查反应和反应产物的细胞区室化，包括用分离的空泡对生成的谷胱甘肽缀合物衍生物进行转运研究。

Phytochelatin synthase not only catalyzes the heavy metal-dependent synthesis of phytochelatins but also serves as a catalyst for the key step in the turnover of lutathione conjugates in plants, the formation of g-glutamyl-cysteinyl conjugates. The latter function has recently been assigned by in vitro analyses. The project proposes now to test and corroborate the newly identified function of PCS in vivo. The analysis will focus on Arabidopsis by using plants, protoplasts and plant cell cultures. Mutants of Arabidopsis impaired in or lacking PCS will be analyzed for glutathione-conjugate turnover and phenotypic alterations. In addition, it is planned to transiently modulate phytochelatin synthase gene expression in order to assess its functions. The cellular compartmentation of both the reaction and of the reaction product will be examined including transport studies of the generated glutathioneconjugate derivative with isolated vacuoles.