Isolation and Characterization of Cytokinin Metabolic Enzymes

细胞因子是一类在细胞分裂和分化过程中起重要作用的植物激素。控制植物细胞分裂素适当水平的机制尚不清楚。该研究项目的长期目标是确定控制菜豆属细胞分裂素代谢的调控元件。最近的研究发现了菜豆胚胎细胞分裂素代谢的遗传差异，鉴定了新的玉米素代谢物，并分离了三种细胞分裂素特异性酶。由于这些酶的活性具有物种特异性，产生的代谢产物比母体化合物具有更高的生物活性，因此关键代谢酶的选择性表达可能是调节活性细胞分裂素水平的重要机制。为了阐明这些酶的代谢控制机制，我们建议进一步对这些酶进行表征，制备单克隆抗体用于检测这些酶在不同发育阶段的活性，并对这些酶的调控和表达进行分子分析。这项工作对于建立一个管理高等植物激素代谢的整体控制的工作模型具有重要意义。细胞分裂素是一组调节植物生长和细胞分裂的激素。这项工作旨在分离和鉴定这些植物激素及其功能的各个方面，以更好地了解植物生长。

Cytokin are a group of plant hormones which play an important role in cell division and differentiation. The mechanisms controlling the appropriate levels of cytokinins in plants are poorly understood. The long term goal of the research project is to identify regulatory elements controlling cytokinin metabolism in the genus Phaseolus. Recent findings led to the discovery of genetic differences in cytokinin metabolism in Phaseolus embryos, identification of novel zeatin metabolites and isolation of three cytokinin specific enzymes. As the activities of these enzymes are species specific and the resulting metabolites display higher biological activity than the parent compound, selective expression of key metabolic enzymes may be a significant mechanism of regulating active cytokinin levels. To elucidate the metabolic control mechanisms, we propose to further characterize the enzymes, to generate mononclonal anti bodies for detection of enzyme activity at different developmental stages and to conduct molecular analyses of the regulation and expression of these enzymes. The proposed work is important to the formulation of a working model governing the overall controls of hormone metabolism in higher plants. Cytokinins are a group of hormones which regulate plant growth and cell division. The proposal work is designed to isolate and identify aspects of these plant hormones and their functioning to better understand plant growth.