阿拉伯芥超氧歧化?調控之研究

Abstract

多數的逆境會造成植物體內超氧分子的增加，而超氧歧化?（SOD）的酵素功能則能有效地清除具破壞性的超氧分子。SOD可依其內含不同的金屬離子（銅/鋅、錳或鐵）而區分為三大類型，並存在於細胞中不同的胞器內。 本論文，以研究阿拉伯芥SOD之調控機制為主；利用原態電泳、SOD活性分析與西方墨點分析來檢測阿拉伯芥生長與發育的過程中SOD的變化，並分析在不同非生物性逆境下，其SOD變化的模式。用蛋白質合成抑制劑環己醯亞胺阻斷細胞中「轉譯」的進行，證實SOD「轉譯後」的調控確實存在，並分析探討細胞內CuZnSOD「轉譯後」的調控機制。也利用金屬離子處理SOD轉殖株，分析金屬離子裝嵌入SOD蛋白質內的機制，並首次提出植物細胞內SOD金屬離子裝嵌系統MISS可能的組成與作用模式。

A number of environmental stresses can lead enhanced production of superoxide in plant tissues, and superoxide dismutase (SOD) is used to scavenge this reactive oxygen species. There are three forms of SODs having various cofactors (Cu/Zn, Mn or Fe) at the active site and they are located in the different subcellular sites. In this thesis, I will focus on the study of regulation of SOD in Arabidopsis. Using native PAGE, SOD activity assay and western blot analysis, the variation for SOD in the rosette leaves was observed during its growth and development. The change pattern of SOD in Arabidopsis imposed to several abiotic stresses where also examined. Cycloheximide is used for the study of translational and posttranslational regulation. The posttranslational regulation mechanism of CuZnSOD in Arabidopsis and its ion incorporation system (MISS) will be discussed. This is the first report for MISS hypothesis in higher plants.