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。在植物中控制适当水平的细胞分裂素的机制还知之甚少。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节元件。最近的发现导致了在菜豆胚胎中细胞分裂素代谢的遗传差异的发现，新的玉米素代谢物的鉴定和三种细胞分裂素特异性酶的分离。由于这些酶的活性具有物种特异性，所产生的代谢物显示出比亲本化合物更高的生物学活性，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。为了阐明代谢调控机制，我们建议进一步研究这些酶的特性，制备用于检测不同发育阶段酶活性的单抗，并对这些酶的调控和表达进行分子分析。这项拟议的工作对于制定一个管理高等植物激素代谢总体控制的工作模型是重要的。细胞分裂素是一组调节植物生长和细胞分裂的激素。这项提案工作旨在分离和鉴定这些植物激素的各个方面及其功能，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.