Plant Metabolism of Xenobiotics

植物络合素合成酶不仅催化依赖重金属的植物络合素的合成，而且还是植物体内谷氨酰半胱氨酸结合物形成过程中谷氨酰半胱氨酸结合物周转的关键步骤的催化剂。后一种功能最近已被体外分析确定。该项目现在提议在体内测试和证实新发现的PCS的功能。该分析将通过使用植物、原生质体和植物细胞培养来重点研究拟南芥。在PCS受损或缺乏PCS的拟南芥突变体将被分析谷胱甘肽结合物周转和表型变化。此外，为了评估其功能，计划对植物络合蛋白合成酶基因的表达进行瞬时调节。将检查反应和反应产物的细胞分隔，包括生成的带有孤立空泡的谷胱甘肽共轭衍生物的运输研究。

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.